A rooster is a male chicken. Roosters received their names due to the tendency of roosters to "roost" over a clutch of eggs.
The phrase "running around like a chicken with its head cut off" has entered the vernacular to mean a person who is extremely busy but directionless.
In Christian symbolism, the rooster is a familiar Passion symbol. Prior to being arrested by the soldiers, Jesus correctly predicted that Peter would deny Him three times before the rooster crowed on the following morning. 
Also roosters are mentioned in the Bible in Matthew:
- O Jerusalem, Jerusalem, thou that killest the prophets, and stonest them which are sent unto thee, how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not! (Matthew 23:37)
Roosters in Music
The grunge band Alice In Chains wrote a song called The Rooster as an homage to a Vietnam veteran known by that nickname.