Hello, I have just noticed this on one of our ex-batts that we rehomed around a month ago. They have all been growing feathers well, but yesterday I saw a bald area on one hen's neck and a large black area of skin. I can't see any mites, blood or infection, but it looks similar to a blood blister. She is behaving normally. There is no smell and the black area feels like normal skin. I wonder if anyone has seen anything like this before and could advise please? Thank you so much!