A
Abdomen - Area between the keel and the pubic bones.
Abdominal Capacity -  Total Abdominal width and depth.
Abdominal Depth - Distance between the pubic bones and the keel bone.
Abdominal Width - Distance between the two pubic bones.
Abscess - pocket filled with pus.
Acariasis - Mite infestation.
Acute - Description of a disease with a severe or short development, often measured in hours and ending in death or recovery; opposite of chronic.
Air cell - The air space between the two shell membranes, usually at the large end of the egg, that can be plainly seen when an egg is candled.
Albumen - The white of an egg, consisting of outer thin, firm, inner thin, and chalaziferous layers.
Alektorophobia - The fear of chickens.
Allantois - A sac connected to the embryo's abdomen making respiration by the embryo possible; it also stores excretions, absorbs albumen used for food by the embryo, and absorbs calcium from the egg shell for the structural needs of the embryo.
American Breeds - Those breeds developed in America and having common characteristics such as yellow skin, non-feathered shanks, and red earlobes. All lay brown eggs except Lamonas, which lay white eggs.
American Standard of Perfection - Book published by the American Poultry Association describing in detail each breed recognized by that organization.
Amnion - A transparent sac, filled with colorless fluid, surrounding the embryo; the amnion and amniotic fluid protect the developing embryo from shock and permit it to exercise.
Anemia - Deficiency of the blood in quantity or quality due to blood loss or disease, characterized by weakness or pale skin.
Anthelmintic -  An anti-worm drug.
Antibiotic - A soluble chemical produced by a microorganism or fungus and used to destroy or inhibit the growth of bacteria and other microorganisms.
Antibiotic Resistance - Bacteria's ability to mutate in order to survive treatment with antibiotics. Over time, bacteria are able to change their characteristics so that antibiotics cannot kill them. This process happens faster when antibiotics are used very frequently, especially at low doses over long periods of time, which is common on factory farms where antibiotics are added to feed.
Antibody - A natural substance in the blood that recognizes and destroys foreign invaders and that causes an immune response to vaccination or infection.
Antigen - A foreign protein that differs from natural body proteins and therefore stimulates the natural production of antibodies.
Antiseptic - Anything that destroys or inhibits microorganisms responsible for disease, decomposition or fermentation.
Antitoxin - An antibody that neutralizes toxins produced by bacteria.
Arthritis - An inflammation of the joint and surrounding tissue.
Ascaridiasis - A Roundworm infestation.
Ascites - Accumulation of fluid in the abdominal cavity.
Atrophy - Shrinking or wasting away of a body part.
Attenuated - Weakened so as not to produce disease but still induce immunity when used as a vaccine (said of viruses).
Avian - Of, relating to, or characteristic of birds; derived from birds.
Avian egg - The mass of material constituting the bird egg - the shell, shell membranes, albumen, and yolk - that is designed by nature to nourish and protect the true egg.
Avian Pox - A viral disease of Poultry - varieties: wet or dry (also called Fowl Pox or Pox)
Aviculture - The science of raising avian species.
Axial feather - The short wing feather between the primary and secondary flight feathers.

B
Baby chick - Newly hatched chick before it has been fed or watered.
Bacteria - Microscopic single-celled plants that may or may not produce disease. Singular: Bacterium.
Bactericide - Substance that kills bacteria.
Bacterin - A vaccine produced from bacteria or other products.
Bacteriostat - Substance that inhibits or retards bacterial growth.
Ballooning - Distension of the intestine or ceca due to accumulated blood, mucus or other materials.
Benign - Not likely to recur or spread.
Bantam - A small miniature chicken, usually one-fourth to one-fifth the size of regular chickens; frequently called "bantie" or "banty".   Most, but not all, bantams are the likeness of a larger variety of domestic chickens.
Bantam Standard - Book published by the American Bantam Association describing each of the bantam breeds recognized by that organization.
Bantie - another (affectionate) name for Bantam.
Banty - another (affectionate) name for Bantam.
Barny - another (affectionate) name for a Barnyard chicken.
Barnyard chicken - A chicken of mixed breed.
Beak - The bird's bill; the hard protruding mouth part of a bird consisting of an upper part and a lower part; upper and lower mandibles.
Bean - Hard protuberance on the upper mandible of waterfowl.
Beard - The feathers bunched under the beaks of such breeds as Antwerp Belgian, Faverolle, and Houdan, always found in association with 'muffs'.
Bedding - Material scattered on the floor of a chicken coop to absorb moisture and manure.  Commonly used are straw,  hay, pine or other wood shavings or shredded paper, etc. Also called 'litter'.
Biddy - affectionate word for a hen.
Bill - Upper and lower mandibles of waterfowl.
Bill out - The use of the beak to scoop feed out of a trough onto the floor.
Biosecurity - Disease Prevention Management.
Blastoderm - A fertilized true egg.
Blastodisc - A true egg that was not fertilized; also, the site of fertilization on the egg yolk.
Bleaching - The fading of color from the beak, shanks, and vent of a yellow-skinned laying hen.
Blood-Spot - Tiny red spot in a freshly laid egg caused by a ruptured blood vessel in the hen's ovary usually during ovulation.
Bloom - The moist protective coating on a freshly laid egg that dries so fast you rarely see it; also, the peak condition of an exhibition bird.
Blowout - Vent damage caused by laying on oversized egg.  Also called prolapse.
Booster - Vaccination other than the first in a series.
Booted - Having feathers on the shanks and toes.
Botulism - a disease caused by the ingestion of a toxin produced by the Clostridium botulinum bacterium.
Break up - To discourage a hen from setting a nest.
Breast - The forward part of the body between the neck and the keel bone.
Breast blister - Enlarged discolored area or sore in the area of the keel bone.
Breed - A group of chickens within a class having a distinctive body shape and the same general features and weight. Also, pairing a rooster with a hen for the purpose of obtaining fertile eggs.
Breeders - Mature chickens from which fertile eggs are collected. Also, a person who manages such chickens.
Breed True - The characteristic of purebred chicks whereby they resemble both parents.
Broiler or fryer - A young meat-type chicken, usually 9 to 12 weeks of age, of either sex, that can be cooked tender by broiling or frying, usually weighing between 2 1/2 and 3 1/2 pounds. Can weigh up to 6 pounds.
Broiler House - a building in which broiler-type chickens are raised.
Brood - To care for a batch of chicks.  Also, the chicks themselves.
Brooder - Heat source for starting young birds. A mechanical device used to imitate the warmth and protection a mother hen gives her chicks.
Brooding Period - the time between when chicks are hatched until they can be on their own without any heat.
Broody - The maternal instinct causing a female to set or want to hatch eggs.
Broody hen - A hen that through hormonal changes has undergone marked changes in behavior and physiology, including cessation of laying and development of the maternal instincts. A hen that wants to sit on eggs to hatch them and to brood chicks.
Bursa of Fabricius - Cloacal bursa.

C
Cage fed - Description of chickens kept in cages.
Calcium Grit -  Ground oyster (or other shellfish) shell is often called "grit".  It is fed to chickens and digested to replenish the calcium used by the chicken to produce egg shells.  True grit is Sand and small pebbles or crushed granite or marble eaten by a chicken and used by the gizzard to grind up grain and plant fibers. Calcium "grit" does not remain in the gizzard.
Cancer - Malignant tumor that tends to spread.
Cankers - Whitish bumps that erupt to form sores usually on the face or in the mouth.
Candle - To examine the contents on an intact egg with a light.
Candler - The light device used to examine the contents on an intact egg
Cannibalism - The bad habit some chickens have of eating each others flesh, feathers or eggs.
Cape   The narrow feathers between a chicken's neck and back.
Capillariasis - Capillary worm infection.
Capon - A castrated male fowl that has been neutered to increase growth rate. Usually accompanied by underdeveloped comb and wattles and longer hackle, saddle and tail feathers than a normal male.
Carrier - An apparently healthy individual that transmits disease to other individuals.  Also, a container used to transport chickens.
Cauterize - To use a hot iron to burn, sear or destroy tissue.
Cecum - A blind pouch at the juncture of the small and large intestine. (resembles the human appendix); Plural: ceca.
Cephalic - Pertaining to the head or skull.
Cestode - tapeworm.
Cestodiasas - Tapeworm infection.
Chalazae - The two whitish cords on opposite sides of the yolk that hold the yolk in the center of the albumen and serve as a rotating axis to keep the germ cell on the top side of the yolk and next to the heat of the hen's body. Singular - chalaza.
Chalaziferous layer - Thin layer of thick white surrounding the yolk, continuous with the chalazae.
Calcar - The bone protruding from a mature male bird's shank that is surrounded by a horny layer that together, make up the spur.
Check - en egg with a cracked shell, but with the membrane still intact.
Chick - a baby chicken
Chicken - A member of the Pheasant family, chickens probably descended from the Jungle Fowl of Ceylon. Chickens have been domesticated for thousands of years and have been developed into many different breeds and varieties by man. They are an efficient source of protein, producing both meat and eggs. They are one of the most prevalent forms of livestock bred around the world today.
Chick tooth - A tiny, sharp, horny projection on the end of the chick's upper beak used by the chick to peck holes in the shell. Also known as egg tooth.
Chondrodystrophy - Having short bones.
Chook -  Australian term for a hen, also applied to all chickens. (rhymes with "book")
Chorion - A membrane that surrounds both the yolk sac and the amnion; it has no apparent initial function but later fuses with the allantois to form the chorio- allantois membrane.
Chromosome - Microscopic cell containing the genes that carry hereditary determination.
Chronic - Description of a disease having long duration measured in days, months, or even years and being somewhat resistant to treatment; opposite of Acute.
Class - A group of chickens that has been developed in a particular region of the world. Also a group of chickens competing against each other at a show.
Classification - The grouping of purebred chickens according to their place of origin, such as "American" or "Mediterranean".
Clean legged - Having no feathers growing down the shanks.
Clinical - Having disease signs or symptoms that can be readily observed.
Cloaca - The chamber just inside the vent or common opening in birds through which the digestive, excretory, and reproductive tracts come together.
Clubbed down - Down that fails to emerge in an embryo or newly hatched chick, mostly around the neck and vent.
Cluck - The sound a hen makes to comfort her chicks; also, the hen herself.
Clucker - Affectionate word for a mother hen.
Clutch - A batch of eggs that are incubated and hatched together, either in an incubator or in a nest under a hen. (from the old Norse word: "klekja" meaning "to hatch"). also called a "setting"; also, the eggs laid by a hen on consecutive days before she skips a day and begins a new laying cycle.
Coccidiasis -  Infection with coccidial protozoa without showing any signs.
Coccidiosis - A parasitic protozoal infection, usually occurring in damp, unclean housing.
Coccidiostat - A drug used to keep chickens from getting Coccidiosis. ie: Amprolium.
Cock - A male chicken over one year of age; also called a rooster.
Cockerel - A male chicken under one year of age.
Coliform - Any bacteria resembling Escherichia coli bacteri
Coloring chicks - The act of injecting dye into a fertile egg so that the chicks hatches with colored fluff.
Comb - The fleshy, red outgrowth on top of a fowl's head; there are eight types of combs.
Condition - A chicken's state of health and cleanliness.
Conformation - A chicken's body structure.
Congested - Filled with blood.
Congenital - Existing at birth but not hereditary.
Conjunctiva - Mucus membrane covering the eyeball and inner surface of the eyelid.
Conjunctivitis - Infection of the conjunctiva.
Contagious -Description of a disease that's readily transmitted from one individual or flock to another.
Contract Grower - Farmer who makes an agreement with an agribusiness company, giving the company the power to make all the farm's decisions, including which animals are raised there, what they are fed, and how they are treated. In return the company pays the farmer and buys the supplies.
Coop - The house or cage in which a chicken lives.
Crest - A puff of feathers on the heads of breeds such as Houdan, Silkie or Polish. Also called a "topknot".
Crop - A pouch at the base of a chicken's neck that bulges after the bird has eaten. It stores and prepares food for digestion; also, (v.) to trim a bird's wattles.
Crossbred - The offspring of parents of different varieties or breeds.
Crossbreed - To mate male and female chickens of different breeds.
Crumbles - a mixture of ground grains and other nutrients, not as fine as 'mash'.
Cull - To eliminate a non-productive or inferior chicken from a flock.  Also, (n.) the non-productive or inferior chicken itself.
Culling - The act of removing unsuitable birds from a flock.
Culture - To incubate a sample from a diseased bird for several hours (or days) and look for the presence of bacterial growth.
Cuticle - A secretion of the uterus consisting mainly of protein that serves to partially seal the pores in the egg's shell and acts as a lubricant when the egg is laid; commonly called the bloom.
Cygnet - A baby swan.
Cyst - A sack-like structure containing fluid or semi-solid material.

D
Dam - Mother.
Dam Family - Sibling chickens that all have the same dam as well as sire.
Debeak - To remove a portion of a bird's top beak to prevent feather pulling or cannibalism.
Defect - Any characteristic that makes a chicken less than perfect.
Dehydration - Loss of body water  (over 12% loss results in death).
Depopulate - To get rid of an entire flock.
Dermatitis - Inflammation of the skin.
Dewlap - the single flap of skin below the beak of turkeys and some geese.
Diarrhea - Frequent, runny bowel movements.
Diathesis - Susceptibility to certain diseases.
Dirties - Eggs with dirt or stains covering more than 1/4 of the shell.
Disease - Any departure from normal health or impairment of normal bodily functions.
Disinfectant - Anything used to destroy disease-causing organisms.
Disqualification - A defect or deformity serious enough to bar a chicken from a show.
Dominecker or Dominicker -Colloquialism for the Dominique breed, often erroneously applied to Barred Plymouth Rocks.
Double Yolker - egg containing two or more yolks.
Down - Soft, fine, hair-like feathers on a chick or young birds. Also, the soft fluffy part near the bottom of any feather.
Drake - Male duck.
Drench - To give liquid medication orally; also, the liquid medication itself.
Droppings - Chicken manure.
Dry-Bulb Thermometer - expresses air temperature reading in number of degrees Fahrenheit (F) or centigrade/Celsius (C).
Dub - To surgically remove a bird's comb and waddles close to the head.
Duck - Any member of the family Anatidae and specifically the female.
Duckling - The young of the family Anatidae.
Duodenal loop - The upper small intestine (same as duodenum)
Dust or Dust Bath - The habit chickens have of thrashing around in soft soil to clean their feathers and discourage body parasites.

E
Earlobes - The fleshy patch of bare skin below the ears varying in size and shape with the color red, white, blue, or purple, according to the breed.
Ectoparasite - An external parasite.
Edema - Accumulation of excessive fluid in swollen or damaged tissues.
Egg - The microscopic cell of the female; the true egg; the female germ cell.
Egg Sizes - Shell eggs are divided by size (class) according to weight. Minimum net weight per dozen:
Jumbo - 30 ounces. Extra Large - 27 ounces. Large - 24 ounces. Medium - 21 ounces. Small - 18 ounces.
Egg tooth - A tiny, sharp, horny projection on the end of the chick's upper beak used by the chick to peck holes in (pip) the shell. Also known as chick tooth.
Electrolytes - Natural chemicals in the blood needed by body cells to maintain balance; also, a mineral solution used to treat dehydration.
Emaciation - Wasting away of the body.
Embryo - The developing chick within the egg.
Embryology - The study of the formation and development of embryos.
Embryonation - Development of an embryo into a larva inside an egg without hatching.
Encephalitis - Inflammation of the brain.
Endoparasite - Internal parasite.
Enteric - Affecting the intestines.
Enteritis - Inflammation of the intestine.
Enteropathogens - Microbes that cause enteritis.
Enterotoxin - A substance that poisons cells lining the intestines.
Enzootic - The continuing presence of a disease or infectious agent in a specific area (equivalent to 'Endemic' human diseases.
Epidemic - A rapid spreading infectious disease situation in humans. (often used for poultry or other animals as well)
Epizootic - epidemic among chickens or other animals (similar to the word 'epidemic' pertaining to humans).
Epidemiologist - Medical Professional specially trained to test for, detect, and deal with epidemic diseases.
Esophagus - Channel that moves food from the throat to the stomach.
Etiology - The study of causes of diseases.
Evaporation - changing of moisture (liquid) into vapor (gas).
Eversion - Turned inside out.
Exhibition Breeds - chickens bred, kept and shown for their beauty rather than their ability to produce eggs or meat.
Extra embryonic membranes - Membranes outside the embryo's body that make respiration, nutrition, and secretion possible and provide protection; they include the yolk sac, amnion, allantois, and chorion.
Exudate - Fluid associated with an inflammation or swelling.
Exudative Diathesis - Accumulation of fluid (exudate) under the skin or around the heart.

F
Face - skin around and below the eyes.
Factory Farm - A large-scale industrial site where many animals (generally chickens, turkeys, cattle, or pigs) are confined and treated with hormones and antibiotics to maximize growth and prevent disease. The animals produce much more waste than the surrounding land can handle. These operations are associated with various environmental hazards as well as cruelty to animals.
Fake - The dishonest practice of concealing a defect or disqualification from a potential buyer or a show judge.
Family Farm - Farm on which the ownership and management are controlled by at least one family member who lives on the farm, not by a corporation or absentee owner.The day-to-day labor and management is provided by the farmer and/or farm family that owns or leases the production or production equipment.
Fart egg - very small egg containing no yolk, also called a wind egg or rooster egg.
Fat - organic combination of carbon, hydrogen, and oxygen in such relative quantities that the caloric value of the compound is high.
Feather legged - Having feathers growing down the shanks.
Fecal - Pertaining to feces.
Feces - Droppings or bodily waste.
Feral - Wild, untamed, not domesticated.
Fertile - An egg that is fertilized; the capability of an egg to develop into a chick.
Fertility - The quality or state of being fertile.
Fertilization - The act or process of making or becoming fertile; the union of a male cell with a female cell.
Fertilized - An egg containing a sperm.
Finish - The amount of fat beneath the skin of a meat bird.
Flaccid - limp.
Flight feathers - Primary feathers of the wing, sometimes used to denote the primaries and secondaries.
Flock - A group of chickens living together.
Fluff - Downy feathers around the vent of a fowl.
Fluke - Trematode flatworm parasite.
Follicle - Thin highly vascular ovarian tissue containing the growing ovum.
Fomites - Inanimate objects such as shipping crates, feed sacks, clothing, and shoe soles that may harbor disease-causing organisms and may be either a vehicle or a reservoir of infection.
Footcandle - The density of light striking each and every point on a segment of the inside surface of an imaginary one foot radius sphere with a one candlepower source at the center.
Forage - To search for naturally occurring nourishment.
Forced-air Incubator - A mechanical device for hatching fertile eggs that contains a fan to circulate warm air.
Forced molt - Part of a hen's natural reproductive cycle. After laying eggs for about a year, a hen loses her feathers and rests for a few weeks as new feathers grow in. This is called molting, or a molt, and it usually happens at the beginning of winter. On factory farms, hens are subjected to forced molting, where farm operators cause this process to happen rapidly by depriving hens of food for several days and altering the schedule of light and darkness in the confinement building. This way, all the hens molt simultaneously and over a very short time period.
Fowl - Domesticated birds raised for food; also, a stewing hen.
Fowl Pox - Highly contagious disease of poultry spread by mosquitos.
Free Range - This term refers to animals (usually poultry, and the eggs that they produce) that are not confined, meaning that these animals are able to go outdoors to engage in natural behaviors. It does not necessarily mean that the products are cruelty-free or antibiotic-free, or that the animals spend the majority of their time outdoors.
Frizzle - Feathers that curl rather than lay flat; also, a chicken with such feathers.
Fryer - A tender young meat-type chicken, usually 9 to 12 weeks of age, of either sex, that can be cooked tender by broiling or frying, usually weighing between 2 1/2 and 3 1/2 pounds. Can weigh up to 5 pounds.
Fungus - A plant that does not contain chlorophyll and that reproduces through spores (plural: fungi)

G
Gallus domesticus - The domestic chicken.
Gallus gallus - The Red Jungle Fowl; also called gallus bankiva. The origin of all current chicken breeds.
Gamebirds - Any of several species including Pheasant, Quail and Partridge/Grouse that have traditionally been hunted for food and sport. Gamebirds may be raised in captivity but are not domestic in the senses that chickens are. The term can also be used for Wild turkey and some species of wild waterfowl.
Gander - Male goose.
Gangrene - Dead tissue that has no blood supply and no pain receptors.
Genes - Parts of chromosomes that carry hereditary factors.
Genetic - Pertaining to genes.
Genus - A group of closely related animals or plants which differ from one another in only slight characteristics.
Germinal disc - Site of fertilization on the egg yolk; blastodisc
Germs - disease carrying microbes.
Giblets - term used to describe the portion of poultry carcasses that consists of hearts, gizzards, and livers. Giblet packages should contain approximately equal numbers of each of those parts. Although not a giblet, the neck is usually included in the same package as the giblets when that package is put back into whole poultry carcasses.
Gizzard - An internal organ of birds.  Muscular stomach.  It has thick muscular walls and a tough lining. It crushes and grinds foods by muscular action and with pebbles or rock grit.
Go light - Grow thin while eating ravenously, synonym for anemia.
Goose - A female goose as distinguished from the gander.
Gosling - A young goose of either sex.
Grade - To sort eggs according to their interior and exterior qualities.
Grit - Sand and small pebbles (insoluble material) eaten by a chicken and used by the gizzard to grind up grain and plant fibers. This is often available at feed stores in the form of crushed granite or marble.  Ground oyster shell is often called "grit", but the purpose is NOT the same.  It is fed to chickens and digested to replenish the calcium used by the chicken to produce egg shells. It does not remain in the gizzard.
Gross - Can be seen with the naked eye.
Gross lesions - Easily observable changes in tissues or organs.
Ground fed - Free to move about outdoors, as opposed to housed and fed within a building or cage.
Guinea Fowl - A pheasant like bird from Africa raised for ornamental qualities, meat, feathers for crafts and fly tying, or vermin control. They are gregarious, and very interesting. They are watchful and territorial making them good natural alarms. They can be noisy, tend to be only partially domesticated and if allowed to roam will cover a fairly wide range.
Gullet - The tubular structure leading from the mouth to the glandular stomach; the esophagus.

H
Hackles - A rooster's cape feathers. 'Sex feathers' on the side and rear of the neck of a fowl. The ends are usually pointed in males and rounded in females.
Hackle feathers - see Hackles.
Hatch - The process by which a chick comes out of the egg; also, a group of chicks that come out of their shells at roughly the same time. Also, a breed of game chicken used for fighting.
Hatchability - The quality or state of being hatchable; also, the percentage of eggs that hatch under incubation.
Hatchery -  a place where eggs are incubated and hatched.
Hatching egg - A fertilized egg stored in a way that does not destroy its ability to hatch.
Helminth - A category of parasitic worm.
Helminthiasas - Parasitic worm infestation.
Hemorrhage - Heavy or uncontrolled bleeding.
Hen - A female chicken over one year or age.
Hen feathered - The characteristic of a rooster having rounded rather than pointed 'sex feathers'.
Hepatitis -Inflammation of the liver.
Hock - the 'knee' joint of a chicken's leg, between the lower thigh and the shank.
Horizontal transmission - Transmitted from one bird to another.
Horn - Term used to describe various color shadings in the beak of some breeds of fowl such as the Rhode Island Red.
Host - A bird (or other animal) in or on which an infectious agent lives.
Hover - Canopy used on brooder stoves to hold heat near the floor when brooding young stock.
Humidity - The amount of moisture in the air in the incubator; 50 to 55 percent relative humidity is ideal the first 18 days of incubation and about 65 percent the last three days.
Hybrid - The offspring of a hen and rooster of different breeds, each of which might themselves be crossbred; often erroneously applied to the offspring of a hen and rooster of different strains within a breed.

I
Ilium - Lower small intestine.
Immune - Resistant.
Immunosuppressant - Any cause of reduced disease resistance.
Immunity - Ability to resist infection.
Immunity, Active - Resistance to a disease as a result of having had the disease or having been vaccinated against it.
Immunity, Passive - Resistance to a disease as a result of injection with antiserum.
Immunoglobulin - Antigen.
Impaction - The blockage of a body passage or cavity such as the crop or cloaca.
Inbred - The offspring of closely related parents; resulting from inbreeding.
Incidence - Number of cases of a particular disease diagnosed during a particular time period.
Incrossbred - The offspring from crossing inbred parents of the same or different breeds.
Incubate - To apply and maintain proper heat and humidity, either naturally or artificially, to eggs to cause them to hatch.
Incubation Period - The time it takes for an egg to hatch; also, the time it takes from exposure to a disease causing agent until the first symptom appears.
Incubator - An artificially heated container for hatching eggs. In a still-air incubator the air is not circulated mechanically. Forced-air incubators have a fan or fans to circulate the air.
Infection - The entry of an organism into a body and causing disease by developing or multiplying within.
Infectious - Capable of invading living tissue and multiplying therein causing disease.
Infertile - An egg that is not fertilized, will not hatch.
Infertility - The temporary or permanent inability to reproduce.
Inflammation - Reaction of tissue to injury or irritation, whereby it becomes red, hot, swollen, painful and possibly loses function.
Infundibulum - The funnel end of the oviduct that picks up the yolk when it is released from the ovary; the area in which fertilization of the true egg takes place; also called funnel.
Ingest - To eat, to take internally.
Initial Vaccination - First vaccination in a series.
Inoculate - To give an injection.
Inoculant - A substance that is injected.
Intensity of lay - The number of eggs a hen lays in a given time.
Intramuscular (IM) - Placement of an injection into muscle tissue.
Intraocular - In the eye.
Intranasal - In the nose.
Intravenous (IV) - Placement of an injection into a vein.
Irradiation - Exposure to radiation. Meat is sometimes irradiated to kill micro-organisms and reduce the number of microbes present due to unsanitary practices, but this process alters the nutritional quality and creates new chemicals that can be harmful to the humans who consume the meat.
Isthmus - The section of the oviduct next to the magnum where the water and mineral salts are deposited and the inner and outer shell membranes are formed.
...itis - suffix indicating inflammation
IU - International unit in which some drugs are measured.

J
Jejunum - Middle small intestine.
Joint ill - Arthritis.

K
Keel - The breastbone which resembles the keel of a boat.
Keet - A Guinea Fowl chick.

L
Laceration - jagged wound.
Large Fowl: The original sized chicken (as opposed to Bantams) Large fowl typically range in size from 4 pounds to 13 pounds. They encompass most of the varieties of chickens people are familiar with but are often larger than many people realize. Light breeds of large fowl are primarily egg layers and lay white shelled eggs. Heavier breeds include the utility and meat breeds and typically lay brown eggs.
Layer - Mature female chicken kept for egg production; also called laying hen.
Layer Ration - Any prepared feed containing all nutrients necessary for a layer to produce good quality eggs. This is available in mash, crumbles or pellets.
Leaker - An egg that leaks because the shell and membrane are both broken.
Lesion - Change in size, shape or structure of an internal organ.
Leukosis - A Disease of the blood forming organs.
Litter - Material scattered on the floor of a chicken coop to absorb moisture and manure.  Commonly used are straw, hay, pine or other wood shavings or shredded paper, etc. Also called 'bedding'.
Loose Eggs - Eggs packed in trays, flats, or non-carton containers that have not been sized and candled for quality.
Lymphatic system - Circulating system that contains the immune system's white blood cells.
Lymphoma - Cancer of the lymph system.

M
Magnum - The section of the oviduct next to the infundibulum; the area in which the thick white is deposited and the shape is formed.
Malabsorption - Excessive loss of nutrients through the feces.
Malignant - Tending to worsen, recur or spread; opposite of benign.
Mandible - The upper or lower portion of the beak or bill.
Mash - a mixture of finely ground grains and other nutrients; finer than 'crumbles'. (see Layer Ration)
Mate - The pairing of a rooster with one or more hens; a hen or rooster so paired.
Meat Breeds - Breeds of chickens developed for their quick growth and heavy muscles. These breeds are developed for eating.
Meat-Spot - Tiny white, gray or brown speck in a freshly laid egg caused by a tiny piece of tissue that enters the egg during formation in the hen's oviduct.
Mechanical transmission - Carried on a surface.
Membrane - a thin, soft, pliable sheet or layer of tissue covering an organ.
Metabolic disease - A Disease involving a breakdown in the body's physical or chemical processes.
Metabolism - All the physical and chemical processes that produce and maintain a living body.
Metastasis - The transfer of a disease from one organ to another that it isn't directly touching.
Metastasize - Spread to other tissues or organs.
Microscopic - Cannot be seen with the naked eye.
Mite - A tiny jointed-legged body parasite.
Mold - A type of fungus.
Molt or Moult / Forced molt - Part of a hen's natural reproductive cycle. After laying eggs for about a year, a hen loses her feathers and rests for a few weeks as new feathers grow in. This is called molting, or a molt, and it usually happens at the beginning of winter. On factory farms, hens are subjected to forced molting, where farm operators cause this process to happen rapidly by depriving hens of layer feed for several days and altering the schedule of light and darkness in the confinement building. This way, all the hens molt simultaneously and over a very short time period.
Morbid - Having or causing a death.
Morbidity - Percentage of a flock affected by a disease.
Moribund - Dying.
Mortality - Percentage of a flock killed by a disease.
Moult - see Molt
Mucus - Slimy substance produced by mucus membranes.
Mucus membrane - The lining of body cavities.
Muff - The feathers sticking out from both sides of the face of such breeds as Antwerp Belgian, Faverolle, and Houdan; also called "whiskers". Always found in conjunction with a beard.
Mycosis - Any disease caused by a fungus.
Myopathy - Any disease of the muscles.

N
Necropsy - A postmortem examination (equivalent to a human autopsy).
Necrotic - Pertaining to dead tissue.
Necrotic enteritis - Inflammation and decaying of intestinal tissue.
Nematode - Roundworm.
Neoplasm - A tumor or other abnormal growth.
Nephritis - Inflammation of the kidneys.
Nest - A secluded place where a hen feels she may safely leave her eggs; also, the act of brooding.
Nest egg - A wooden, plastic or ceramic egg placed in a nest to encourage hens to lay there.
Nest run - Ungraded eggs, as laid.
Neural - Pertaining to the nerves.
Noninfectious disease - A disease that is not caused by a biological organism.
Noxious - Unpleasant.
NPIP - National Poultry Improvement Plan
Nutritious - containing substances necessary to sustain life and growth.

O
Ocular - Pertaining to the eye.
Oil sack - Large oil gland on the back at the base of the tail - used to preen or condition the feathers.
Oocyst - The infective fertilized egg of certain one-celled animal parasites including protozoa.
Opportunistic - An organism that is non-infectious to healthy birds; infectious only to birds with reduced resistance from some other cause (stress).
Organic - This term refers to products from animals that have been raised without the use of hormones, antibiotics or genetic engineering, and which has not been irradiated. Vaccines and medicines are allowed for treating illness, but the meat cannot be sold as organic if certain prohibited medicines are used. All feed must be 100% organic. Animals cannot be confined except under certain temporary circumstances such as illness. Organic products must meet very strict standards; national standards for organic food have been passed into law.
Organism - A living thing.
Osteomyelitis - Inflammation of the bone marrow.
Osteopetrosis - Increased size, density and brittleness of the bones.
Osteoporosis - Thinning and weakening of the bones.
Ovary - The organ of the female which holds the true eggs and produces the yolks on which the true eggs are located.
Oviduct - The tubular organ of the female birds that puts the albumen, shell membranes, and the shell of the avian egg around the yolk.
Oviposition - The laying of an egg.
Ovum - The round female germ cells attached to the ovary; plural form is ova. They are releases and drop into the oviduct and become the egg yolk.

P
Papilla - The projection on the shank of a bird that eventually develops and grows into a spur in male birds.
Parasite - An organism that lives on or inside a host animal and derives food or protection from the host without giving anything in return.
Parental immunity - Resistance to disease passed from breeders to their offspring through the egg.
Parenteral - Located outside of the intestines, used in referring to drugs introduced by injection rather than by mouth.
Pasted vent - Droppings stuck to the vent of a chick that can cause death if not removed.
Pasting - Loose droppings sticking to vent area.
Pathogen - Disease producing organism or agent.
Pathogenic - Capable of causing disease.
Pathogenecity - Degree of ability to cause disease.
Pathologist - A medical professional who examines internal damage caused by disease.
Pathology - The study of damage caused by disease.
Pecking Order - The social rank of chickens.
Pediculosis - Louse infection.
Pellets - see Layer Ration
Pen - A group of chickens entered into a show and judged together; also, a group of chickens housed together for breeding purposes.
Pendulous crop - Crop that is usually impacted and enlarged and hangs down in an abnormal manner.
Peracute - Having extremely severe and short duration, measured in minutes or hours.
Perosis - Malformation of the hock joint.
Perch - The place where a chicken sleeps at night; also, the act of resting on a perch; also called a roost.
Persistancy of lay - The ability of a hen to lay steadily over along period of time.
pH - A number that indicates acidity or alkalinity; 7 is neutral, above 7 is alkaline, below 7 is acid.
Pheasant - A species of gamebird that comes in many breeds and varieties. They are raised for meat, feathers, ornamental value or to be released into the wild.
Pickout - Vent damage caused by laying on oversized egg.  Also called prolapse or blowout.
Pigmentation - The color of a chicken's beak, shanks and vent.
Pinbones - Pubic bones.
Pinfeathers - The tips of newly emerging feathers.
Pip - To break through or peck holes in the shell by the chick; the hole a newly formed chick makes in it's shell.
Pituitary gland - A small kidney-shaped gland located at the base of the brain that produces hormones involved in sexual maturity, the maturation and release of yolks, and egg laying.
Plumage - The total set of feathers covering a chicken or other fowl.
Pneumonia - Any disease of the lungs.
Popeye - Emaciation of chicks (causing eyes to look large in relation to the body).
Pores - thousands of microscopic openings in the shell of an egg through which gases are exchanged.
Post - To conduct a postmortem examination.
Postmortem - Pertaining to or occurring after death.
Poult - A young turkey.
Poultry - Chickens and other domesticated birds raised for food.
Pox - A viral disease of Poultry - varieties: wet or dry (also called Fowl Pox or Avian Pox)
Predator - One animal that hunts another for food.
Predispose - To cause susceptibility to disease.
Prevalence - The number of cases of a disease in a flock during a given time.
Primary flight feathers - The last 10 feathers on the end of a chicken's wing.  These are sometimes clipped to 25 or 50% of their length (on one wing only) to prevent flight.
Priming vaccination - Vaccination that increases antibody levels before another product is used to induce immunity.
Primitive streak - A vertical, opaque line where the embryo begins to grow and develop.
Processor - A person or firm that kills, cleans and packages meat birds.
Producer - A person or firm that raises meat birds or layers.
Production Breed - Any breed of chicken bred specifically for high egg production and is usually not appropriate for exhibition or meat.
Progeny test - Evaluation of breeders based on the performance of their offspring.
Prolapse - Slipping of a body part from it's normal position.
Prolapsed vent - damaged vent caused by laying on oversized egg. A portion of the oviduct extends outside the vent. Also called "prolapsed oviduct", "blowout" or "ickout".
Protective synergism - Phenomenon by which two vaccines confer greater protection than the sum of their individual effects.
Protein - one of a group of nitrogenous compounds commonly known as amino acids.
Protozoan - A single-celled microscopic animal that may be either parasitic or beneficial; plural: protozoa.
Proventriculus - A chicken's stomach, lying between the crop and gizzard.
Pubic bones - Two sharp, slender bones that end in front of the vent; also called "pinbones".
Pullet - A female chicken under one year of age.
Purebred - The offspring of purebred parents that are of the same class, breed, and variety.
Purulent - Full of pus.
Pus - Liquid produced by inflammation, containing dead white blood cells.

R
Rales - Any abnormal sounds coming from the airways.
Range fed - Description of chickens that are allowed to range pasture.
Ration - The combination of all feed consumed in a day.
Ratite - The family of birds including Ostriches, Emus and Rheas.
Rattling - Abnormal sounds coming from the throat.
Reactor - Bird that reacts positively to a test for an infectious disease.
Recycle - To force into a molt with a cessation of egg production.
Relative humidity - The percentage of moisture saturation of air.
Renal - Pertaining to the kidneys.
Render - Subjecting disposed animal carcasses to grinding, extraction, heat or other treatments to convert into by-products for use in feed rations and fertilizers.
Replacements - Term used to describe young birds that will replace an older flock.
Reportable disease - A disease so serious it must, by law, be reported to a state or federal veterinarian.
Reservoir of infection - Any animate or inanimate object on which an infectious agent survives and multiplies and from which it can be transmitted to a susceptible host.
Resistance - Immunity to infection.
Respiration rate - Number of cycles per minute by which air is moved into and out of the lungs.
Restricted egg - A check, dirty, leaker or otherwise inedible egg.
Rhinitis - Inflammation of the lining of the nasal passages.
Rigor mortis - Stiffness following death.
Roaster - A young meat-type chicken, usually 3 to 5 months of age, of either sex, that can be cooked tender by roasting, and usually weighing 4 pounds or over.
Roost - The place where a chicken sleeps at night; also, the act of resting on a roost; also called a perch.
Rooster - A male chicken over one year of age; also called a cock.
Rooster egg - very small egg containing no yolk, also called a wind egg or fart egg. (NOT actually laid be roosters)
Roup - Any condition involving chronic infection of skull membranes, characterized by facial swelling.

S
Saddle - The part of a chicken's back just before the tail.
Saddle Feathers - 'sex feathers' on a chicken's saddle.  The ends are pointed in males and rounded in females.
Salmonella - A type of bacteria that causes food poisoning and is commonly found in meat and animal waste, particularly poultry.
Salpingitis - Inflammation of the oviduct.
Scales - The small, hard overlapping plates on a chicken's shanks and toes.
Scratch - The habit chickens have of scraping their claws against the ground to dig up tasty things to eat; also, any grain fed to chickens.
Scratcher - Affectionate name given to a range-fed (free range) chicken.
Secondaries - The large wing feathers closest to the body, visible when the wing is folded or extended.
Secondary infection - A disease that invades after a bird's immune defenses have been weakened by some other disease.
Secretion - Fluid coming from a body organ.
Seleniferous - High in selenium.
Self-limiting - Any disease that runs its course in a specific amount of time then stops without treatment.
Septicemia - Blood poisoning or invasion of the bloodstream by a microorganism.
Serological - Pertaining to the testing of blood serum for antibodies against specific diseases.
Set - To put eggs under a broody hen or in an incubator to hatch them.
Setting - A group of hatching eggs in an incubator or under a hen; also, the incubation of eggs by a hen. (often incorrectly called "sitting").
Sexed chicks - Day-old chicks with the males and females separated.
Sex feathers - Hackle, Saddle and Tail feathers whose ends are pointed in males and rounded in females. (except in breeds in which the males are "hen-feathered" such as Sebrights).
Sex Link - Any inherited factor linked to the sex chromosomes of either parent.  Plumage color differences between the male and female progeny of some crosses is an example of sex-linkage. Useful in sexing day-old chicks.
Shank - The part of a chicken's leg between the claw and the first joint ('hock' or knee joint).
Shell - The hard outer surface of an egg made up largely of calcium carbonate; the shell has pores allowing loss of carbon dioxide and moisture from the egg.
Shell membranes - Two thin membranes next to the shell and surrounding the albumen and yolk; known as inner and outer shell membranes; they are one of the egg's chief defenses against bacterial invasion.
Sickles - The long, curved tail feathers of some roosters.
Sign - Objective evidence of disease consisting of symptoms and lesions.
Sinus - A hollow space or cavity.
Sinusitis - Inflammation of the sinus cavities.
Sire - Father
Sire family - The offspring of one rooster mated to one or more hens so that all are full or half siblings.
Slip - A male from which all of both testicles was not removed during the caponizing operation. (mistake).
Small farm - Farm that earns no more than $250,000 per year and on which the day-to-day labor and management is provided by the farmer and/or farm family that owns or leases the production or production equipment. This does not necessarily mean that the farm is organic or cruelty free, or even that it is not controlled by a major agricultural company.
Smut - Black feathers are uncharacteristic for a breed such as black body feathers on a Rhode Island Red.
Snood - Fleshy appendage on the face of a turkey that hangs down alongside the beak.
Spent - no longer laying well.
Sperm or Spermatozoa - The microscopic cell of the male; the male germ cell capable of fertilizing the ova.
Splayed Legs - Infliction preventing a chick from standing upright.  Legs will be sdpread out the the side.  Usually caused by too slippery a surface in incubator or brooder. Alsp called Spraddle Legs.
Spleen - Organ near the stomach that aids in the functioning of blood.
Spore - The seed of fungi or the inactive form of certain bacteria.
Sport - Genetic Mutation that occurs naturally or is induced (for example: by radiation); also, cockfighting.
spp. - (as in Salmonella spp.) more than one species.
Spraddle legs - Infliction preventing a chick from standing upright.  Legs will be sdpread out the the side.  Usually caused by too slippery a surface in incubator or brooder. Alsp called Splated Legs.
Spur - The sharp horny protrusion from the inside rear of a bird's shanks, usually a cock or rooster.
Squab - Baby pigeon, either male or female, also called squeaker.
Stag - A cockerel on the verge of maturity, when his comb and spurs begin to develop.
Standard - The description of an ideal specimen for a breed; also, a chicken that conforms to the description of its breed in the American Standard of Perfection.  Sometimes erroneously used to refer to large as opposed to bantam breeds.
Standard Sized - See Large Fowl.
Started pullets - Female chickens that are partially grown, usually to point of lay that is about 20 weeks of age, by specialized growers for sale to egg farmers.
Starter - A feed ration for newly hatched chicks.
Starve-out - The failure of chicks to eat.
Steal -A hen's instinctive habit of hiding her eggs.
Sterile - Permanent disability to reproduce.
Sternum - Breastbone or keel.
Stewing chicken - A mature female chicken, usually more than 10 months of age; that requires moist, pressurized, or extended cooking; also called hen or fowl.
Stigma - The suture line or non-vascular area where the follicle ruptures when the mature ovum is dropped.
Still-air incubator - A mechanical device for hatching fertile eggs that does NOT contain a fan to circulate warm air.
Straightbred - Purebred.
Straight-run chicks - Day-old chicks that have not been separated according to sexes.
Strain - A group of birds within a variety that has been bred by one person or firm for some time and has more or less uniform characteristics and capabilities.
Strain cross - The offspring of parents of two or more different strains belonging to the same variety.
Stress - Any physical or mental tension that reduces resistance to disease.
Stub - Down on the shank or toe of a clean-legged chicken.
Subclinical - An inapparent infection for which signs or symptoms can be detected only through laboratory analysis.
Subcutaneous - Directly beneath the skin.
Swan - A large elegant species of waterfowl with breeds native around the world. Some breeds are raised for their ornamental qualities.
Symptom - Detectable evidence of a disease.
Syndrome - A group of symptoms that occur in combination in a particular disease, such as runting syndrome.
Synergistic - Working in cooperation ( same as synergetic).
Syringe - Tube with plunger that holds a drug to be injected.
Systemic - Involving the entire body.

T
Taeniasis - Obsolete word for cestodiasis (tapeworm infection).
Temperature - The level of heat in the incubator; can vary from 99° to 103° F. 99.5° F is optimum in a forced air incubator and 102° F is optimum for a still-air incubator, measured at the level of the top of the eggs.
Tenderloin - This boneless-skinless white meat is the pectoralis minor muscle. It comes from the inside of the breast adjacent to the keel bone. Tenderloins are marketed fresh or frozen.
Tenosynovitis - Inflammation of the synovial shield of a tendon.
Testicles or Testes - The male sex glands, located alongside the backbone on a male fowl.
Three host tick - A tick that spends the three stages of its life on three different hosts.
Tin hen - A metal incubator.
Tom - a male turkey.
Torticollis - Twisted or wry neck.
Toxemia - Generalized poisoning resulting from circulation through the body of toxins produced by bacteria.
Toxin - A poison produced by microorganisms.
Toxoid - An agent that confers immunity against toxins produced by bacteria.
Trachea - Windpipe. That part of the respiratory system that conveys air from the larynx to the bronchi  and the lungs.
Transovarian transmission - Infection of a hen's egg prior to the shell being formed.
Trauma - Wound or injury that destroys tissue.
Traumatic ventriculitis - Piercing of the gizzard by a pointed object.
Trematode - A parasitic fluke.
Trio - A cock and two hens or a cockerel and two pullets of the same breed and variety.
Tubercle - a tumor like mass.
Tumor - A mass of tissue that develops and grows without benefit to surrounding tissue.
Turn - The act of changing the position of eggs being incubated to prevent the embryos from sticking to the shell membranes.
Turkey - A large game bird native to the Americas. Wild turkeys are found throughout North and South America and there are a number of domesticated breeds. Males are called toms, females called hens and chicks are known as poults.
Type - The size and shape of a chicken that tells you what breed it is.

U
Ulcer - A raw, red sore.
Undercolor - Color of the down part of the plumage.
Undergrade - Edible shell eggs that do not meet the requirements (standards) for Grade AA, Grade A, Grade B, or Checks.
Unthrifty - Unhealthy appearing and/or failing to grow at a normal rate.
Urates - Uric Acid (salts found in urine).
Uremia - Poisoning caused by accumulated wastes in the body, usually due to kidney failure.
Urolith - Urinary stone.
Uropygial gland - Oil sack; Large oil gland on the back at the base of the tail - used to preen or condition the feathers.
Uterus - The section of the oviduct next to the isthmus where final portions of the white and minerals are deposited and shell and shell pigment are added.
Utility Breeds - the traditional "barnyard" birds, bred for a combination of egg laying abilities and meat production capabilities. These are all-purpose breeds.

V
Vaccine - Product made from disease-causing organisms and used to produce immunity.
Vagina - The section of the oviduct next to the uterus in which the cuticle is deposited on the shell and the eggs are turned completely around on its long axis so that the large end is laid first.
Variety - A subdivision of a breed, distinguished by color, color pattern, kind of comb, beard or leg feathering.
Vascular - Pertaining to blood vessels.
Vector - A living thing that carries disease organisms within its body from one source to another (examples: mosquitos, ticks, flies).
Vehicle - Anything that mechanically carries disease organisms from one place to another (examples: clothing, equipment, dust).
Vent - The common outside opening of the cloaca in birds through which the intestinal, urinary, and reproductive tracts empty.
Venipuncture - Inserting a needle into a vein for the purpose of drawing blood.
Ventriculus - The gizzard.
Vertebrae - Bones in the spinal column.
Vertical transmission - Transmitted from parent to offspring through hatching eggs.
Veterinary ethology - The study of animal behavior as it relates to health.
Viremic - Of or pertaining to a virus in the blood.
Virulence - Strength of an organism's ability to cause disease.
Viscera - Internal body organs and glands.
Viscous - Thick and sticky.
Virulence - Pathogenicity or ability to cause disease.
Virus - An ultra-microscopic organism that multiplies only in living cells.
Vitamin - a fat- or water-soluble substance necessary, in very small amounts, for normal growth and maintenance of life. Solution added to poultry water or sprinkled over feed.
Vitelline membrane - Thin membrane that encloses the ovum.

W
Warfarin - An anticoagulant used to poison rodents.
Wattles - The fleshy, red growths that hang from the side and base of the chicken's beak.
Wet-bulb thermometer - a device used to measure the amount of moisture or water vapor in the air.
Whiskers - see Muffs.
Wind egg - very small egg containing no yolk (fart egg).
Windpuffs - Air trapped under the skin as a result of rupturing the air sacks during caponization.
Wing Clipping -  procedure used to prevent flight in which the Primary Flight Feathers are cut to 25 or 50% of their length.  

X
Xanthophylls -  the typical yellow pigments of leaves, grasses and green plants that, once ingested by poultry, tend to darken their egg yolks. Many people attribute the dark yolks of "free range" eggs to the insects eaten by the hens rather than this pigment in grasses which is the actual cause.

Y
Yolk - Ovum, the round yellow mass upon which the true egg is located and that provides nutrients for the developing embryo.
Yolk sac - The follicle where an ovum and its surrounding yolk are held until the yolk matures and is released.

Z
Zoning - Laws regulating or restricting the use of land for a particular purpose such as raising chickens.
Zoonosis - A disease transmissible from a chicken (or other animal) to a human (plural: zoonoses).