A filly at a stud I worked at got caught up on a gate out in the field, same type of injury and her's was also on her ribcage. Washed it daily, kept it clean and it healed quickly enough. She did have a mark left but it never affected her again.
I would also be very concerned about the horses running in and out of the stalls. In a herd situation there is always going to be bullying, and it is down right dangerous that the horses be put in a situation that they are trapped in a stall without the ability to get away from the other horses. I would think that this is a very serious accident waiting to happen.
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.