We have 3 Buff Orps along with 2 White Plymouth Rocks. All are 20 weeks old. Margo, the largest of Buff's has feathers from the back of her neck missing. There are no mites or fleas on her or the others, When I hold her and pet her she loves it. I tried to look under her feathers and all I can see is that there is a shaft for each feather and very little fluffy stuff on each. They do not look broken or plucked out. She has been this way as long as I can remember. Just a fluke or has anyone else experienced this? Also, is it normal for chickens to loose feathers occasionally? Not to molt, but just to have them laying around the run floor?:/