Chin chewed by another chin.
My experiences with furchewing
I've only run into chewing on a few occasions; Four were rescues that eventually quit with good care and a stable environment. Two others that did not. Another was a breeder that started when she had her kit - the kit has never chewed, but mom is now 6, still chewing (dang near bald with a mohawk!) and in a pet home. Next incident was a mosaic I purchased from the Whitewoods. Around 8 months of age she started to chew. She seemed to quit around 12 months so I introduced her to the male above. Two days later he had that patch on his side and she went to a pet home.
I have also seen cases where under undue stress chins will do anything from just chewing the top off of the tail to stripping the entire tail. Moms will strip babies bald, or chew on them, and babies will chew on moms. Males will pull the fur out of their chests, or strip the tails of every female in the run. I have only seen these things occur in larger breeding operations or in very cramped caging conditions. One herd I saw recently had a large number of females that pulled the fur from around the inside of their thighs when they aged over a year. Every single female was traced back to a particular male 3-6 generations back, and the breeder chose to cull them to pet homes.
It is my opinion that while the chewing chin may be chewing from an environmental stress that can be removed or remidied, I have 20 or 30 other healthy non-chewing animals that are in the same situation. Therefore I have no tolerance for it in my herd.
Tan chinchilla fur chewing itself.
This photo was sent to me by a breeder when I inquired about this animal. They claimed that the chin was being chewed by its cage buddy. Remember the mohawk I mentioned earlier? It is left behind because she can not reach that portion of her back.