I have a buff, who I thought was moulting, but is not. She has a bare spot on her back (about 2 x2), and it has been that way since winter. She is the only one in my flock- which makes me think she is either being picked on by the others (although I've never witnessed this), or perhaps picking her own back. Should I worry about this (it's not spreading), is there something (like a spray), that I can put on her back to make it stop? Help appreciated!