My only explanation for Brunhilde's not very flattering haircut (it's almost a mullet!) is the other chickens - I can't imagine a predator got that close without actually hurting her. Plus it's been over the course of a couple of days, a few more feathers each day. There is no rooster so she's not being mounted. What's weird is I thought she was at the top of the pecking order. I haven't seen any of the others (there are four - two her age and two younger) doing anything to her.
How can I figure out who it is? And is she likely to get hurt or should I not worry? They are almost ready to lay - any day now as they are 22 weeks old.