A
Addled: Means that a fertile egg either didn't develop during the incubation process or the chick died before it hatched.
Alektorophobia: fear of chickens.
Avian Influenza: Bird flu.
Axial feather: When the wing of a chicken is opened out, you will see along the edge, a single layer of feathers sticking out. Roughly in the middle is a shorter feather, and this is the axial feather. The axial feather shows where the primary and secondary feathers begin and end.

B
Bantam: A small chicken.
Banty (plural: banties): affectionate term for a bantam.
Beak: The hard bit on the front of the head through which they breath and eat.
Bedding: The stuff put in the bottom of a coop to absorb moisture and smell e.g. wood shavings, straw, hay.
Billing out: Using the beak to scoop food out of the feeder and therefore waste it.
Bloom: the moist, protective layer that, unless you see the hen lay the egg, you will never see because it dries so fast. If you wash the egg then you remove the bloom, which is why it is not recommended.
BLR: Abbreviation of blue laced red, a colour most often seen in wyandottes.
Booted: having feathers on the feet and legs.
Breed: 1. A group of chickens that all look alike - "a breed of chicken". 2. To put a cockeral (or rooster) together with a hen so that they mate and produce fertile eggs.
Breeders: 1. Chickens which are put together so that they will mate and produce fertile eggs. 2. A person who breeds chickens.
Broiler: A young, tender chicken destined to be eaten early on in life. Not to be confused with broiler house.
Broiler house: An extremely inhumane way of raising chickens for meat. The chickens (broilers) are put into a huge, overcrowded shed (often containing hundreds of thousands of chickens) with little thought for their welfare, and then slaughtered at around 6 weeks of age.
Brood: 1. A group of chicks, often hatched out together. 2. To care for chicks.
Brooder: A heated cage in which chicks live until they do not need the heat that a mother would normally give them.
Broody: A hen that wants to hatch out eggs.

C
Candle: To use a light to examine the contents of an egg without breaking the shell. Often used to see if embryos are still alive in the egg.
Candler: A device used to candle an egg. A torch (flashlight) is often used for the purpose.
Cannibalism: When a chicken eats 1. The eggs 2. The feathers 3. The flesh (of a living bird).
Cape: The feathers between the head and the body of the chickens.
Carrier: 1. An outwardly healthy chicken that gives other chickens a disease. 2. A box in which chickens are transported.
Chick: a baby member of the chicken species, male or female. Used in UK and US.
Chicken: refers to the species.
Chooks: Australian term for chickens.
Clean Legged: To have no feathers on the legs or feet.
Clutch: 1. A batch of eggs that are incubated together. 2. All the eggs layed by a hen on consecutive days before she skips a day and starts a new laying cycle.
Coccidiosis: A parasitic protozoal infestation, usually occurring in damp, unclean housing conditions.
Coccidiostat: A drug used to keep chickens from getting coccidiosis
Cock: A male chicken over one year of age. UK term.