Has your vet ruled out mycoplasma arthritis? It's just that you mention she won't get up. MA is extremely debilitating and can be such a painful condition that pigs can't be asked to get up and about as normal, go off their food, and consequently start losing condition and strength. I've had a few with it and it's completely curable. There are two antibiotics that will sort it - lincomycin (Lincocin) and Tiamulin. The other antibiotics don't seem to touch it, but both of these will get them up on their legs within 24 hours. Worth talking to your vet about.