My first thought is that she has spent way too much time on her back legs, such as when standing on a fence. But I do admit that I haven't seen this problem before, and haven't had the time to really dig into the research this evening. I'm not looking forward to learning about this, since physical structure problems in a three-year-old are going to be hard to fix.
The current owner says that she is getting feed and minerals, and her color looks ok. Her fleece is pretty matted (it's very fine, and likely has lice), and will be coming off next week. That should give me a chance to really see what she looks like, and whether a vet visit is warranted.
