I would repeat this washing again tomorrow morning to try and soften this hard scab. It looks like she may have been badly pecked and it has become infected. It also could be a tumor or cyst possibly, but since it is on the back, I would treat it as a peck injury first. I might try soaking her in warm Epsom salts or the Hibiclens for up to 30 minutes, and then try to wash off some of the softened scab with a rag. Then dry her and apply a plain antibiotic ointment twice a day. Another picture after the next washing would be good. Make sure that she is away from flies, and that she is eating and drinking. Cooked egg, chicken feed, tuna are all good.
Today I caught one of our other chickens peck Nugget around her chest/wing area. We brought her in and this is what we found. It’s a hard lump. We tried washing it with hibiclens. It smells rotten but there is no discharge. Nothing washed off of it, like dirt or anything. She doesn’t act like it hurts at all. She rather enjoyed the warm water running on her . It is very big but today is the first I have noticed it.
