If the ulcer remedy suggestions don’t work, I’d move him to a different barn. I went through this two years ago with my mare. After three months at the crazy making barn, I finally moved her to a different barn and the difference was like night and day. She instantly settled down at the new place and we went for a trail ride THAT DAY. There was something at the other barn that she did not like, and I’ll never know what it was. But if it ever happened again I would not waste three months of our lives waiting for it to pass, I now know that!