Okay, I'll get a picture tomorrow. Her skin is black and the spots don't appear to be any darker than the rest of her body.
Some of them are in the saddle area, but I seriously doubt they're rubs from the saddle because a) saddle rubs are usually nastier than just missing hair, b) I've been using the same pad on her for years and the same saddle for months, c) they appeared after she hadn't been ridden in a few days, d) they appeared when I had started blanketing after not doing so for a couple weeks, and e) I had just changed her blanket. The ones that aren't in the saddle area are on her hip bones.
Anyway, some of the spots still have hair, but it's seriously thinned out. The other spots have hair, but it looks like it was shaved. The hair is very short. None of the spots are hairless, nor do they look irritated at all.
Does that sound like blanket rubs? Are they usually on the shoulders? Because her shoulders look perfectly fine...
Thanks for the pictures!