Poor girl. With my post before, I wasn't trying to make her weight seem trivial by stating how others are.....just that she should come back from it fairly easy. Sometimes with email things don't get expressed right, and I didn't want you tho think I was being snarky or anything.
I would definatly call the police, see what is on record. I would also file a complaint with the state vet.....especially if there is another horse still there. Were the people fallen on hard times, or was it due to neglect? I am sure that would play into your decision. I got a QH gelding last January, he was a fairly big time show horse (WP) and he was hideous when I went to see him. horrible feet, you could see his vertibrea and pelvis. He was low man on the totem pole, her other horses were fat and happy (they were all together in a run in situation) and she was on a tight budget so didnt feed "extra". So, I took him home, got him healthy and found out he's a psycho (LOL, that's another story! ) but it didnt take long with all thehay he wanted and a diet approved by my vet. I think it was 4 months, and you couldn't tell it was the same horse. So, have faith, she will look good shortly. In the mean time, do you blanket her? If not, she might benefit from it right now, so she doesn't use up her energy trying to stay warm. Just a thought.
Does she remember you? I bet she is happy to be in familiar surroundings. Hugs to her....... and you.