Terminology
In the UK, Ireland and Australia adult male chickens over the age of 12 months are primarily known as cocks, whereas in America and Canada they are more commonly called roosters. Males under a year old are cockerels. Castrated roosters are called capons (surgical and chemical castration are now illegal in some parts of the world). Females over a year old are known as hens and younger females as pullets although in the egg laying industry, a pullet becomes a hen when she begins to lay eggs at 16 to 20 weeks of age. In Australia and New Zealand (also sometimes in Britain), there is a generic term chook ( /ˈtʃʊk/) to describe all ages and both sexes. Babies are called chicks and the meat is called chicken.
"Chicken" originally referred to chicks, not the species itself. The species as a whole was then called domestic fowl, or just fowl. This use of "chicken" survives in the phrase "Hen and Chickens", sometimes used as a British public house or theatre name, and to name groups of one large and many small rocks or islands in the sea (see for example Hen and Chicken Islands).
In the Deep South of the United States chickens are also referred to by the slang term yardbird.
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