I'm not familiar with frizzles but I'm guessing they do moult like other birds. But they molt all over, not just in one area.
Roosters prefer one or two hens to mate with and will take the feathers off the tops of their heads and their backs by overmating.
If this isn't the case, it won't hurt to treat for mites. Google "chicken mites" or do a search here. I've heard people using Sevin dust, and directly dusting the chickens themselves, as well as sanitizing the coop and using the dust in the coop too. They aren't contagious to humans THANK GOD
Could be mites but...Frizzles are the worst for losing back and neck feathers.The feather's are soft and the roo's will tear them up easily.I had one hen they kept pecking and pulling her's that I had to pen her and put sunblock on her back becuase she got so bare.You might consider chicken saddles for her if you cannot keep her away from the roo's.
We just have one rooster who is full sized he has 23 other hens so I hope he's not picking on poor Fluffy!! Cause he is way bigger than her! I will try dusting her with DE and see if that helps as well. Thanks everyone!
That's her oil gland. You should cut an oval out of fleece and two slits for her wings and one for her tail- that way she's protected. Even if the roo isn't the cause, he could slice her with his toenails when she's bare like that. I had a hen fillet-ed like that, and she was a mess! It took a lot for her to heal.
Also: My monster-sized boy is madly in love w/ my banty Cochin...I wouldn't be surprised a bit if he's the cause. My guy has 20 other gal-pals, too.