Hey before you put Horses in those stalls ... you need to cover up that Tin on the inside of the stalls. Pretty sure you dont want a Vet bill or have to put a horse down due to them kicking thru the wall.
Oh 100% Bandit! We'll be lining all the stalls that will home animals with OSB, at least 4-5' high. Thankfully this isn't the first barn we've rigged up for horses & goats, lol. Learned quite a bit with the barn my in-law's built about 10 years ago. We've heard horror stories about accidents like you've described though. Not on our watch! ;)