Unbullied featherless hen?

[ellie97]

I have a seven or eight year old Frizzle hen, and she's a little odd. For about three year she has had a serious lack of feathers. She has some, but only about a third as many as she should be-just in patches. At first I assumed the roosters were picking on her, but several months ago we sold the roosters and the feathers haven't grown back in at all. The other hens don't pick on her-she gets along very well with them. Also, I don't think she lays eggs-if she does, they are far and few-she's never in the nesting boxes. She does fine in the Winter-the other hens will lay on her to keep her warm. Any ideas? Skin problems? Just slow to grow back? I'll post a picture ASAP...