These evening when I closed my chickens in, I noticed that one rooster was taking particular interest in one of the hens and the hen was obviously disturbed. The rooster would make a half-hearted attempt at mounted the hen, the hen crouched, the rooster got off, went in front of the hen and bit the hen's comb. Not just a little peck, he grabbed on and yanked and held on. He drew blood. This rooster is generally very well behaved, I've never seen this sort of behavior. I put the hen in a different pen for the night and the rooster isn't picking on anyone else. Just curious if anyone can suggest what is going on.