I have 10 RIRs and 9 SLWs. All but one of the Wyandottes have picked their feathers around the oil gland. One of them now has a naked & red bum as well. I've read all about lice, but I can't see any, even at night. A couple of them seem to be thinning feathers around the base of their combs. But here's the weird part: none of the RIRs have any feathers missing, though a couple of them also seem to have thinning feathers on their heads. The food trough has one of those bars that turns so the chickens can't perch on it...could that be rubbing head feathers off? Everyone shakes their head when sitting on the roost under the heat lamps, until they go to sleep. These girls are about 9 months old and have not yet gone through a molt. Here's my question: Is it lice or molt (or none of the above) causing one breed to pick feathers?