In my personal experience, on the fenceline where the ugly stallion is, I would put an electric fence that would knock him on his butt when he hit it. We have had up to 3 stallions at any given time and I have electric fence up. They have been pastured next to the neihbors mares and my mares and even right next to each other and they know that the fence means stop or it will nail them. I have only ever had 4 foot fences and once they have learned what electric fence is they never have tried to jump it or anything, no stallion fights between any of them and no escaped horses.
You know how to make a miniature horse even smaller? Leave them in the dryer a little longer!
"Don't ever regret something that once made you smile"