A cockerel is a young rooster, a male chicken which has not been castrated.
The term comes from the Old English cockerel, which is a diminutive form of Cook, or “rooster.” At one time, adult male chickens were referred to as cocks, but when this term acquired a new definition in slang, the word “rooster” came into being.
Cockerels has several traits which distinguish them from hens, often at a very early age. When chicks are first born, it is usually difficult to distinguish between males and females, but within weeks, cockerels have markedly pronounced combs on their heads, and they may appear bulkier, with longer and more decorative tail feathers.
A cockerel often looks particularly sleek and graceful, since the bird has not yet bulked out or begun fighting to defend territory with other birds, although cockerels can and will squabble if left alone with each other.
He fighting instinct of roosters is world famous, and in some regions, roosters are actually bred specifically for fighting as a blood sport.
by Jordan Donaire Gil