horse aggressiveness

Question
Hi, I have at my barn a mini mare, and a 13 year old gelding. I just purchased a Percheron gelding. He has been there about a week, and I eased the two geldings together in the same paddock without any incident. The mini mare stays seperate. Now the gelding tried to be dominant until the Percheron came in the same paddock, and told him he was dominant. Now the Percheron is nipping myself, and a guest I had brought to the barn. Today, a few friends were walking through the paddock where he was located (the gelding was in a seperate paddock) and within 6 feet of these friends he threw a buck they believed to be aggressive and territorial. I think since he has only been at my barn a short time, he is still trying to find his position there. I won't stand for nipping or dominance with humans. Been told he is a very calm, wonderful, slow horse for beginners. Past owners never saw aggression issues. Is this just a new territory incident?  If not, I won't keep a horse that is this kind of problem. Thanks

Answer
Hi Tami,
Any time a new horse is brought into a herd, it has to find its way into the pecking order. This is natural. You and any other human who associates with it become part of the herd. The horse cares less what species you are. And by the way, any animal with the horse (be it one or ten), is a herd. So, if it is just you and your horse, you become a herd. One of you has to be the leader. If you don't step up and lead, then the horse will. The horse is trying to establish and show its position in the herd by nipping, bucking and kicking out.
I would put this horse to work. I mean some hard, out of breath, sweat pouring off his back, I can't take it anymore, type of work. You have to gain his respect. You gain a horse's respect by moving its feet forward, backward, left and right. Do this in a roundpen. Constant changes of direction will get his attention and let him know YOU are number one and he is number two.
I would also ignore the nipping. Before you fall out of your chair and think I'm nuts, read on. When I say "ignore", I don't mean don't do anything about it. Just don't make a big deal of it. Pretend it never happens. But when it does, be prepared to act swiftly by bringing your elbow up hard into his nose. Let him feel the pain of him "running into your elbow". To the horse, he would have done it to himself and not you hitting him. This normally stops it after a few times. But as soon as you do it and it's over, forget it like it never happened. If this doesn't work, you may have to increase the action. If you are walking by your horse or standing there and he reaches out to bite, WHACK the hell out of his nose. I mean lay back and let him have it!!! But again, act like nothing ever happened as soon as it's over. AGAIN, before you say, "This guy is nuts!!! Hitting a horse is horrible!!!!!". Think about what horses do in the pasture. What do you think the alpha mare would do to him if he were to walk up and bit her in the pasture?? She would spin around, bare her teeth, bite him back, kick him and send him off to the other end of the pasture until he showed he would show her the respect she demands. Horses show no mercy to other horses in a pasture when they act up. But if the offending horse comes up afterwards and gives the mare her space and acts out of respect, all is forgiven and the will graze side by side. This is waht you will be doing. If you're not prepared to do this, then expect the problem to only grow worse. And it will happen fast. Now it's just nipping and a little buck. Very soon, it will grow and escalate into a more aggressive and dangerous manner. You do not have to be mean to your horse, just show the horse that you will not tolorate this kind of behavior.
An afterthought....alot of folks out there have the misconception that your actions will make the horse "head-shy". It will not. Standing there beating your horse over the head with a two-by-four will make a head-shy horse. But repremanding strongly by a swift whack will not.
Also, make sure you act as soon as it happens. Waiting and going back to do it means nothing to the horse. A horses has a very good "long-term" memory. But its "short-term" memory is very short. Only about 3 seconds long. So if you wait over about 3-4 seconds before you act, it will mean nothing to him. He won't know why he got the whack. It has to be done immediatly after the bad behavior.
To sum it up, Put your horse to work in the round pen moving his feet forwards, backwards, left and right. And be ready to bring a swift and just repremand to him if he should try to harm you.
Step in there and take charge as the alfa mare.
I hope this has answered your question and has helped you. Please stay safe and enjoy your relationship with your horse.