I have had an ameraucana hen and a bantam cochin hen for a few years. The ameraucana is an older hen, still laying. I introduced my mini-flock of 2 bantam cochins; a cockerel and a pullet, and 2 easter egger pullets, all about 4-5 months old. My ameraucana hen is suddenly very aggressive toward the cockerel. She is usually sweet. Today though, she was chasing and attacking him. His comb and earlobe were bleeding. I separated the aggressive hen from the flock. I know to keep her out for a few days, but is there anything else i should do about the behavior? Here is a picture of the hen.