I don't know blob, but I have a hen like that too, and I almost got rid of our rooster too. But I think our hen is starting to molt. How old are your hens?
Another one of our hens is losing tail feathers and neck feathers, and I think she's molting too. Otherwise, I do wonder if the one with the bald patch on her back might have mites. I'd rather it be molting than mites.
Bob - My hens that are starting to lose feathers are 1 yr. 4 months. It could be molting.
There is a molting thread under "Online Poultry Show" in the next topic box down - you might want to look at some of those chickens and see if they look anything like yours. Or just search under "molting" and see if it sounds familiar.