Hi all! one of my hens has had a bald spot on her back. she is not moulting, she is not being pecked at, it looks like some of the feathers have been broken. It is cold here, so I feel she needs her feathers for warmth. Do I have to pluck those feathers out to encourage new ones to grow? If I need to do this--will she bleed, and if she bleeds--do I need to isolater her TIA!