Have had this deer on camera a lot in the last month or so. I have asked the Wisconsin DNR what the issue might be with this deer. This is what I was told from Lindsey Long, DVM, DACVPM, with WDNR: "When I look at this image, to me it actually looks as if what you are seeing is the "plush" layer of the fur. Basically, the guard hairs look as if they aren't present. If that what the deer is exhibiting, the most common cause on the sides like in the image is typically excessive grooming. There can be many different things that could cause that: ectoparasites in or on the skin or abdominal pain would be the highest on my list for free-ranging animals, in captivity it can occur as a neurological response to captivity. Obviously, that is just a professional guess based on the pictures ".
I hope that helps shed a little light on the original post picture