Yesterday my mom came back into the house after feeding the chickens, yelling, "I [censored] hate Itchy!" While she was scooping feed out of the bin, Itchy had attacked her. Pecked and kicked his feet at her leg. So I told her to come with me to the coop (we're keeping them in the coop for the winter since there's no point in letting them out when there's no vegetation available outside, and it's below freezing point). I wanted to see Itchy's aggressiveness myself. He refused to do so while I was there, but did his usual pre-emptive strike behaviours - rolling his head back, flapping his wings, charging and backing off. So I grabbed him and held him gently but firmly, as the other four chickens ran to the other side of the coop, clucking away. He struggled again and again, tossing up his legs to try and claw me. I just held him in place, gently telling him, "No. Calm down." I let him go and he ran around me to rejoin his flock. Then I noticed the feathers. Lots of feathers, scattered around the floor of the coop. I checked all the chickens. Quiet Hen and Yappy (the two adult hens) were missing feathers on their backs, near the tail end. I know that it is Itchy causing this damage - I caught him mounting the hens in the past, aggressively holding them in place (clenching the feathers on their neck in his beak, gripping their back tightly with his feet). I figured that back then he was younger, he needed practise, and would be more gentle when he got older. But it's gotten worse, the hens are losing their feathers. They can't afford to lose their feathers during the winter, when the windchill can get to -40. Scratchy, Itchy's brother, is calm and submissive, and therefore is incapable of causing such damage. The most he does to the hens is clean their feathers affectionately. I suppose part of the problem is that my mom has a fear of chickens. The first time she tried touching one of these chickens, Itchy was behind her, and scared the crap out of her when he crowed for the very first time. She uses a stick to tap Itchy on the chest/neck whenever he becomes aggressive toward her, but from what I've gathered it doesn't have any effect. I don't want to get rid of Itchy in any way, as he is Scatchy's only companion (the other three ignore Scratchy). My parents think it's a good idea to set up some chicken wire in the coop and put Itchy in isolation there, where he can't abuse the hens any longer but still be with them. I don't know what to do, to be honest.