A squirrel got in the coop and they have lots of bumps and scratches from their mites and other bugs. One of my chickens has it really bad, something bit her on her eyelid and now its swollen almost shut. They are black on top and are mostly on the middle aged flock which is about 6-7 months old. The older ones don't really have it, and the baby ones don't have a single bite. We put sevins dust on the one, but it didn't work. Is there a medicine I can put on the chickens faces to make it go away or is it a medicine they can eat, also does anyone know what this could be?