I only have three hens, it's winter here so they spend most of the time all cooped up. Although they do have a large coop and fenced in and roofed run. But my top hen has started plucking the other two girls feathers out. I noticed it a few days ago. She's picking mostly at the smallest chicken I have.. But I did notice today she has begun doing the same thing to the third hen. I thought maybe is was lack of protein since they can't fee range like in the spring. So I've been feeding them meal worms and scrambled eggs so they get the nutrients they need. Not working, is she bored? I throw bird seed into the run daily but they tend to lose interest quickly. What can I do or does she need to go?