Well, after my last post, she had a set back. One of the front legs went completely limp, so the vet told me to double the antibiotic. She started using the other front leg and that leg is completely back to normal. There was no further improvement until today. She is now putting weight on the last bad leg.
We redid her WBC count, and it is much closer to normal. The xray shows great bone density in general, so she does not have MBD. I didn't think that was possible with her diet, uvb, and supplements. Her lungs are also completely clear. But there are soft tissue changes and some bone changes in the elbow of the bad leg, so we think she had a systemic infection of some kind that settled in those front legs, and more in the right front leg, which is still swollen and not fully functional. It was either that or she somehow got injured and there was a secondary infection.
So, we will give antibiotics for 10 more days. He said that she will always have some issues with that one leg, but will be fine for the most part. She has gained weight since our last vet visit, and I think she is doing better by herself, at least for now, so I plan to just keep her separate. 
