"Matted" area on Trixie's back

I mentioned this in another thread, and was asked to post a few more pictures of the area on Trixie's back I am concerned about. A couple folks mentioned it may be fur biting. Here are some pictures I hope are better. If biting is the case, what can I do about it? I am including a link to the other thread, with the older picture, for comparison. I cannot post the picture twice. The picture of Trixie outside her dust bath is older

http://www.chins-n-hedgies.com/forums/showthread.php?t=13100&highlight=matted

That last picture, the one with the dust bath, it really looks like fur chewing to me.

If that's what it is, there's nothing you can do about it. Some chins just do it. Some will stop eventually, but others don't

The other ones it looks like chewing to me too, it's just clearer in the older one because it's more in focus.

Fur chewing can be stress related, like one of my girls will chew if we move, but otherwise she doesn't. But for some chins it's just what they do. Or sometimes it can be due to boredom.

If she's got plenty of toys and a wheel and gets attention and nothing major has changed recently then I'd say it's just something she does. It's not anything to worry about and it's not going to hurt her.