Picking or ?

[KorLaut]

I have a Rhode Island Red who has a 'thing' going on with her wing. About an inch of it is bare skin, and there are beginnings of new feathers, but they don't grow. The quills surrounding the bare spot are still there but the quills are bare from the skin to halfway up the quill. I've had her isolated for the better part of a month and I have been blue coating it every few days. Maybe she is pecking at her feathers or could there be something else? I've checked her for mites and she doesn't have any. Or at least appear to have any.

Any ideas?