As an instructor and trainer, I have dealt with herd-bound horses a lot. What has worked for me is this: Ride the horse away from the herd/barn until the horse wants to go back. Then go back to the barn, turn around and ride away again right away. Do this over and over until the horse realizes that going back to the barn just means he has to turn around and go away again. Let him make the choice. You might only gain a foot each time. Keep at it. I have had this take 50 trips until the horse gives up and goes peacefully away from the barn. Works like a charm, but you must have patience. Do not punish the horse, just ride quietly to and from the barn. I have not had this method fail. (I did not invent this method – I got it from Clinton Anderson). Whenever possible, let the horse have a choice for behavior. When he makes the right choice, life gets easier for him. They figure it out.