I just got home from work and went to check on my chickens. I noticed one(named Red) had feathers sticking up on the back if her head. I got a hold of her and it looks like something pulled a silver dollar sized chunk of her skin and feathers out. No other injuries to the other hens, no blood or feathers anywhere that I can see on the coop or run. The wound has stopped bleeding and has dries blood around and on it. how do I clean it? How often do I clean it? Should I separate her from the others? None of the hens have ever been aggressive. I don't know how it happened. I can post pics if needed. Thanks!