A couple months ago, we noticed that one of the chickens in our flock was never leaving the coop to go outside in the run and had feathers plucked out. Upon further experimentation and testing we realized that she was being bullied. Every time she went out into the run the other chickens attacked her until she ran back in. Now, 2 months later, I've got 4 chickens that are in the coop that refuse to go out into the run, for the same reason. They are being plucked alive. I feel so bad for them. I can't figure out how to stop this behavior. The run and coop are plenty big (I have 12 chickens) I often toss in scratch and garden produce to keep them busy. I can't figure out who the instigator is. Whenever I put one of the bullied chickens in the run, 3 or 4 of them come right up to her and start pecking her until she runs back in the coop. Any advice that you have to stop this behavior would be greatly appreciated!