I really need some help..My 12 yr TW is being very mean to our 32 year old horse and our other 12 yr..He is worst to the older one. He runs him off chases him wont let him in the barn. Its very upsetting because he is so old he will not fight back. He does it some to the other horse but not as bad, she will atleast get in the barn. I also have a mule and they get along pretty good.. I really don't know what do do, we don't have stalls so I can't close him up, but oh how I would like to...The barn is plenty big enough for all of them. We had6 horses and during the summer they would all be in the barn, sometimes the older would be to, but most of the time he would just put his head in..Now my TW wont even let him do that...We sold two of the horse a couple of months ago so its just the four of them and they have been together for 5 or 6 years if not longer..The TW has always kind of been aggressive towards these two, but not this bad..