Hi! I apologize in advance if this is an over-asked question. We have four hens and one roo. The roo and three hens are SLWs. The smallest hen (one of the SLWs) has developed a small bald spot with a red chapped looking area on her back right at the base of her tailfeathers. I haven't seen her OR the other hens pecking at her back. What could be causing this, and is there anything I should do about it? They chickens have a lot of room in the coop, and are allowed out to free range in a large back yard two or three times a week. I haven't noticed anything like it on any of the other hens. Thanks for your help!