I bought a four year old ranch breed mustang three months ago, and I havent had to put him in a stall. Being out in the pasture with my other two horses he got attached, and the last two times I put him in the stalls with the other horses he was fine when they were in there. But the minute I pulled one of the other horses out to put them in the pasture he would ram his stall door with his chest and bust it open. I know I could just put him out first, but I don't want him to think this behavior is alright. Any suggestions?