I have a hen who has suddenly made a hobby out of pulling one of my roo's neck feathers. she pulls them from directly in front and an one side of his neck. I checked for bugs, found no trace. He is going through molt, and I can see pin feathers on the front of his neck, but on the side where she has been picking there are only broken feather shafts. He just stands there and lets her do it. She's not eating the feathers, so I know its not related to nutrition.