http://www.asiasentinel.com/society/welcome-to-the-year-of-the-cock/
You may see many references to the Year of the Rooster. This is wrong usage. It derives from puritanical minds which cannot accommodate the fact that cock in English, has long had a secondary meaning, clearly derived from the first, referring to the male sexual organ.
A cock is a male fowl. A hen is a female. A cockerel is a young cock. A rooster is a type of cock – a roosting cock – placed with hens to encourage them to lay eggs. A roost is a perch on which the fowls sit (and to which chickens come home).