I have one girl (golden laced wyandotte) that picks feathers off my other chickens and eats them. Their food is 19% protein, so I don't think protein is the problem. I have added Black Oil Sunflower Seeds to their diet for the past week, and there is still no change in her behavior. She just keep picking feathers - the downy ones - a lot. The other chickens get mad and noisy, but don't do anything. She is the only one with this behavior. Anything else I can do?