Gallus domesticus


Chickens come in many different breeds and a variety of colors. Almost all breeds of chickens have a comb on their heads and wattles under their chins. Females (hens) typically have shorter tails and smaller combs and wattles than the males (roosters). Chickens have four toes on their feet, three pointing forwards and one pointing backwards.


Chickens can range in weight from half a pound up to 13 pounds, with most chickens weighing in the 7 to 10 pound range.



The chickens at Cosley Zoo are fed a commercial chicken feed which contains adequate calcium for strong eggshells.


When a hen ovulates, the yolk of an egg is produced. This yolk then travels into the oviduct, where it may be fertilized by sperm from a rooster. As the egg travels farther through the oviduct, it is covered by a membrane and a substance called albumin (egg white). As the egg reaches the bottom of the oviduct, a shell is deposited around it and the egg is laid. It takes about one day for the egg to complete this process. A fertile egg with proper incubation takes about 21 days to develop into a chick. Chickens can lay eggs even if they have not mated with a rooster; therefore, not all eggs are fertile.

Shelter and Space Needs

Farm-raised chickens are given a variety of types of housing, from the conventional chicken coop to free range. Basic chicken needs include access to food and water, a shelter from the weather and predators, room to exercise, and places to roost and nest. Cosley Zoo's chickens have an outside yard as well as an indoor coop where they stay at night. The coop also contains their nest boxes, food and water.

Life Expectancy

The average life expectancy of a chicken raised as a pet is about 8 years.

Importance to Man

Domestic chickens provide people with meat, eggs, and feathers.

Fun Facts