I am new to raising chickens and have recenlty acquired two hens (sisters) and one rooster from a friend who also raises chickens. While I feel that my chickens are happy and healthy, my rooster is very timid with the sisters. He doesn't seem to assert himself and as a result, the sisters chase him around a bit. He was an adopted rooster by my friend who already had a rooster in her flock so my guy was never the "rooster" of the flock. He was the "rooster" in the flock that he was adopted out of. How do I help my rooster to find his authority?