Agressive 4 yr old

If you can't even get him from point a to point b, then you are in over your head. If you were unable to correct him when he initially blew up on a lead line, you are in over your head (regardless of whether someone else was present). If you are not in control, you are in over your head. I agree with all others have said. Get someone with more experience.

Also if you knew how to fix the problem you wouldn't be asking on the forum, and this horse would of been corrected swiftly and severely for its aggression towards you at the first hint of it. If I could talk to your parents I'd tell them not to let you get anywhere near this horse. For him to be "good" then change to aggression shows lack of training and a horse being spoiled. And now this horse will be even worse the next time it tries to boss you. Something I have a feeling he does all the time anyways even when being "good", but you don't have the know how to recognize it. I'm guessing your a teenager so you have the invincibility and I know it all complex that we all get at that age. But listen to us who have been training for many years and have dealt with several horses. You are in danger of being kicked, bitten, ran over, struck, and stomped all if which will be very painful, could break bones, disfigure you, paralyze you, or kill you. You have two options get a trainer and correct the bad behavior, something if you can should watch how they do it, or sell the horse. Get yourself something broke save your body. There are some injuries that even at a young age can stay with you and hurt all the time. Take it from me who suffers from chronic pain due to injury. Please make the smart and mature decision for your own safety.
Posted via Mobile Device

You are now afraid to take the horse out of his stall and lead him across the yard, if you think that horse doesn't know that & isn't going to take full advantage of this, you are kidding yourself. Even if I could give you step by step do it yourself instructions, I would be setting you up to be at the mercy of a large animal that can kill you, sorry I don't want no part of that!
Posted via Mobile Device

I think with all due respect that its time to get the help of a more experienced trainer. If you are training the horse and getting paid its time to seek another opinion and speak to the owner. I think on the ground help is needed because even if we wanted to give you advice we don't know what triggered the behavior. Use this a learning opportunity and work with a trainer to learn how to handle this situation. Find a trainer to work with you. Getting from point A to point B is never the easy part, once you get to B you have to go to C.

I think if you are scared of this horse you are putting yourself at greater risk. You are going to be on edge all the time and expecting bad behavior. Self fulfilling expectations. I would say

Not confusing to me. No offense, but if you knew how to fix the problem, you would have done so the other day. Turning the horse loose to get away from you in a large arena is not the way to fix it, that will just solidify the idea in his mind "Okay, if I act like <this>, I get to run around loose and do as I please" and he'll get worse.

Like others said, since he acted that way once before and didn't get punished for it, he won and you lost. Next time will be exponentially worse.

For your own safety and for the sake of the horse, please get some professional help.

"he's very social, he loves to be pet".....

The above from your second post on this, is the crux of the problem.

You have created a spoiled horse.

Also there is good chance horse is not being aggressive but is just full of himself from being stalled too, and you don't have enough experience to realize that, or deal with it either.

And furthermore, if your brother was riding in the arena? You had no business trying to take an unbroken horse in there period. Doing that is just asking to get someone hurt or killed.

If you don't get some help for your handling of horses as well as how to assess your surroundings you will end up getting hurt badly. Not if, when.

Letting a horse run free when acting up on lead line, is not going to fix anything.

Forget trainer. Sell these, get something already broke, and take lessons on handling horses.

Time to get out the ole shovel handle to knock some sense into him
Posted via Mobile Device

If it were me, I'd throw him in a group of other more mature horses for a while so they can beat the snot out of him. You can't win this fight with him, he's bigger than you. A few grouchy mares would definitely teach him some respect.

Like almost everyone else said, --"You are in way over your head!"

If you had any clue how to 'fix' this, he would not have gotten this way in the first place. ANY "NO!", he did not just start his yesterday. Yesterday may have been the first time he actually struck at you or charged, but I guarantee he sent you warning signals and you missed them all.

Some dominant horses only need a handler that they can step toward and make the handler back up a step or two and they think they are 'in charge'. This horse does not need 'join up'; he needs to be seriously taught that he must back up or move away from his handler absolutely every time the handler asks him to.

He must be taught to stay out of your space and respect you 100%.

He doesn't need to be petted or given treats.

He seriously needs an adult that can show him that this is no acceptable behavior.

He obviously is not a show horse, so there is not reason for him to be stalls. Get him out of a stall, into a pasture or big paddock with other geldings (no mares) where he can get all of the exercise he wants and get him off of 'hot feed'.

If your training had been going well before this, you would not have said "The last few times I worked both of them, they were a little energetic,..."

If your training had been going well, he would have been getting more respectful and easier to handle. If you have been just taking him and turning him out and 'thought' you were teaching him anything positive while he was running around the arena, you were mistaken. He would be nicer and not aggressive. I'll guarantee that he gave you warning signals. I guarantee that at some time, you stepped back away form him when you should have stepped forward and made him back up. You may not have 'read' these signs correctly, but he 'read' your weakness and vulnerability and thought 'it was time for him to send you out of his space.'

Get some help before he gets worse and you get hurt. Most spoiled horses I see at the local horse sale with aggression problems came from a situation just like this. They usually end up on the killer truck.

Seek out a pro.