I have asked a couple breeders about it but they had no more ideas. There probably aren't anymore ideas. Hachiro had a litter over a year ago of triplets. She got irritated from the triplets constantly trying to use the same nipple and started chewing at the irritation. We got her a cream for the irritated skin and separated her from the babies periodically until she healed. Her fur was growing back but as soon as it was nearly back to normal she chewed it all up and looked raggedy again. We could find no health problem. She improved a little but then started getting steadily worse.
We gave her as much cage space as possible and we are not ones to use small breeding run cages. Right now we are working on putting 4 cn together in a rectangle for a pair. We got lots of stuff to chew on. Entire limbs off local trees we know are safe. We trimmed several feet of grapevines and gave that to the chins. We took a wooden pet bird indoor nesting box (very thin pine sheets with nontoxic glue) and stuffed it full of various hays so she ate the hay while chewing the box. Destruction and mayhem ensued but the fur chewing did not improve. We gave her a permanent personal dust bath so she could keep her fur as clean as she wants. Finally totally out of ideas we put her with another chin. Utter disaster. Now I have 2 ragged looking chins.
What else is there to try? Every month it gets worse. The only thing I can think of is to get her out of the cage more but while we try to handle our chins a lot we do have a fair number since we are breeding so out of cage time is a little limited for some. If we did not have a foster dog I would release her in to the spare bedroom for long periods of time but it's occupied right now. The other bedroom is kept at 80F for the hedgehogs and the rest of the rooms have too many hazards for out of cage pets except dogs. I would like to rehome her to a good pet home where they can let her out frequently. Preferably multiple times a day. I am afraid though that they might give up on her fur chewing and leave her to tear herself in to baldness rather than keeping after it and doing what is necessary whichever way things go.
This is how she was in aug
That was really mild chewing. She has giant chunks near completely gone now. She looks so scrawny from the lack of fur. We will take her to the vet another time just to be sure it's not a physical problem but one hasn't been found previously. Maybe the new vet office will have someone knowledgeable that wants to take her home and work on the problem.