Feather loss

[Major Buff Orpington]

One of my Maran hens has a bare neck and I found a load of feathers in the nest box. Could she be doing this to herself and why? If not is it a disease?
Anybody help?

 

[Judy]

If you post in the emergencies section and answer the questions at the beginning of the section, we could probably help. Include how much space, are they confined.