Here's a picture of one of the places I have boarded at/worked in Montana:
You can see rows and rows of those types of 'stalls' they're really common and not make-shift at all. The hill and other surroundings give them a decent wind break and they're perfectly acceptable to me. It also doesn't look small. There is plenty of room there to move around and lay down.
The pictures looked like a warm climate maybe new mexico, arizona, or something like that. The water who knows. I'm not going to judge off those pictures.
I pictured like 2 feet of manure or something but I don't see that picture as being very bad. I don't think you have a leg to stand on for any sort of abuse case.
As far as the stall being not picked out or injuries, I guess that's why it's so important to read your contract and ask questions before you sign. Better luck at your next place.