Cluckingsworth (2012 TV series)

Dr. Cluckingsworth M.D. is a mutant chicken with an oversized brain, which makes him way smarter than the other chickens.

History
Within the Woods - Dr. Cluckingsworth M.D. occurs as a normal chicken with some other chickens, that is fed by Mikey.

Race with the Demon - Dr. Cluckingsworth M.D. was an ordinary chicken until it drank the mutagen sample that came from Speed Demon. The mutation enlarged it's head where it became super-smart and can lay mutagen eggs.