If the horse is going to need to push off the stall wall, CHECK the planks in the wall for how “springy” they are. Because:
When I was a race groom as a kid, the other groom and I arrived early at the barn to feed breakfast before the boss got there. The other groom would start at one end of the shedrow, and I would start at the other, opening doors, putting feed in. I opened one door, and sticking through the wall was a leg, from the horse in the next stall over. She opened that door, and saw the mare, who WAS standing, with her leg caught between the planks, snapped back on her cannon bone. We don’t know exactly how it happened… they were very old, very tough oak planks, not normally considered “springy” at all. But there it was. We dealt with it. The other groom pulled on the plank (injured her back doing this) and I removed the hind leg. We presumed that she had been cast, kicked at the wall attempting to free herself, and the leg went through and the planks snapped back tight on it, and then, somehow, she got up. We presumed it would be broken… but surprisingly, it was not. Badly mangled though, huge long recovery, lots of scar tissue, major injury. The boss arrived, after we had her free, it was a horrific injury. She returned to the races the next year, and won a few more.
But when I walk through other people’s barns, I often see stall walls just like this… planks that have way more “spring” than these old oak ones did. Planks that would “give” if a cast horse was thrashing into them- give, and let a leg through, and snap back hard on the leg. Every barn I have had since then always has a center post mid wall to support the planks. Because of that day, and that injury.
Good luck with a horse who casts itself often. I had one once, home bred filly, who did this. She just didn’t care. She would just lie there, and wait to be rescued. Usually cast in a paddock fence. Daily. Not sick, no colic… she just didn’t care. Eventually, someone told me to beat her with a broom while she was cast, which I was reluctant to do. But eventually, I tried it. To “frighten” her about being caught in the fence, so that she would CARE. It worked. She thought about it, and didn’t do it any more. So there you go, for what it’s worth. YMMV.