Cheryl is right. He needs to be away from his friends. He is a LITTLE herd bound which in normal for his age. You need to be in charge and he needs to respect your space. You can start that in his stall, with his halter and lead. That way you are in a controlled area. Teach him where he needs to stand and that it is not exceptable to be on top of you. If he goes to walk in front of you or walk off bump him back. Until he gets use to things he is going to dance around and you will just have to keep him back where he is suppose to be. As far as the round pen being in use all the time, if you are paying for board you have a right to use it. If someone has been in there for quite a while ask them if they are done. You have just as much right to use it as they do. You can also ask the barn manager if they could put a time limit on the round pen (ie. 30 min per person) That or you might have to find a time to come out when it is not as busy(early morning etc). If you can find a time to use the round pen daily, I would not turn him out with his friends, I would keep him in. And you be the one to let him where off energy in the pen and then work with him. No matter what age mine are if they start getting to attatch to one another I seperate them for a while.

Is he still a stallion? Do you plan to keep him one? If not the sooner you castrate him the better it will be for you and him, and make him a little easier to work with. I personally like to have mine halter and leading before they are weaned, it is just much easier, that way they learn from mom.

Hope this helps. Good luck