A person who wears a bullfeather is a person whose
wife or girlfriend has cheated on him. The term comes from the "horns" on a cuckold -- the
horn being the closest thing a bull has to a feather.
Just about any joke involving horns was considered hilariously funny through the 19th century, because everyone knew it meant the guy was a
fool who was being cheated on -- the worst social disgrace for a man of that era.
John's
wife is having an affair with Peter
Quincy -- can't you see the bullfeathers on his head
Richard's girl sleeps with every guy in
town. What a bullfeather he is!