Update
I just got on and read all your posts from last night. I appreciate your kind words, but anyone would have done the same if they had seen the situation. Mare and baby are back home now. Momma is a bit sore from all the efforts that were made and the 2 hour trailer ride she had to go through. She is mostly laying down today. The vet was very pleased with the progress made on her "good" leg. He said all that killed skin and tissue had to come off for the underneath tissue to heal and it is. It also looks like anything that was going to die from the lack of blood flow already has, so now it just has to heal. She wont loose any more tissue. The biggest problem is keeping the flies and gnats off. We can't bandage it as it needs air really bad. All that dead tissue over the top created quite a bed of infection. I have some various creams and potions to put on it that should help.
He also mentioned that false joint possibility. He said he had seen it in dogs and cats but never in a mini horse, but it could happen. He wasn't very hopeful because of the bone positions in this particular injury, but it could happen. I was really glad to hear that a mini out there somewhere had done it.
As for the "out of joint" phrase, I just used it as it got the point across on what type of injury it was. There is no ball joint in a front shoulder in a horse, but it is exactly as Minimor said. Where the humerous and scapula bones come together is a joint and that is where everything popped apart. In this case, the end of the humerous is sticking way forward causing a huge forward lump in her shoulder. The end of the scapula is about midway on the humerous, on the inside, pointing down. Basically, instead of the shoulder bones making a backwards letter Z, they make an X. She can't bring that leg forward at all, but she does use it for balance a little bit as she hops. It is the humerous that has the fracture at the end.
The plan is to keep her as comfortable and pain free as possible for a few weeks to a month and see what develops. This way, the baby can get the best chance, and we can see if there is any chance of a false joint forming. It will be an uphill battle because the other leg is so debilitated and will have to carry all the weight. Vet says she will very likely founder on that leg, just from having to carry all the load, and I should be prepared. Frankly, another issue is since she has had no supplemental feed, it will be hard to keep weight on her as I have to start so gradually. She can have as much hay as she wants and I am trying to pack as many calories as I can into each cup of feed, but the last thing I need to do to her is cause her to grain founder!! On the other hand, she is rail thin and nursing.
Anyway, we have a plan. Hopefully I am balancing her best chance of survival with quality of life correctly. It is a tough decision. Would it be more humane just to put her down? If she doesn't form that false joint, did I put her through extra weeks of pain for nothing? But what if it does form? Then her life is saved. Lots to figure out. I hope I'm up to the task. For now, it is wait and see.