I don't Know why but my brothers horse doesnt like to take the bit any more. And I am just wondering how I could train him to open his mouth willingly, without aggression. It is harder to bridle him, and check his teeth, file them down. E.c.t
My two QH mares had that problem when I got them - still do, a little bit, but it's a work in progress.
Whenever you are doing anything around him, play with his mouth. A lot. Get him reeeeeal used to having hands on, in, and around his mouth! (Be careful not to get bit though.) Hand-feeding helped my girls a lot. Also, work with going through the motions of getting him to open his mouth -- that is, stick your finger/thumb in his mouth (in that gap behind his front teeth and in front of his molars) and playing with his tongue/rubbing the palate until he opens his mouth. Then take your hand out and reward. Repeat.
When you go to bridle him, don't just jam that bit in his mouth and off you go. Take it slow, as if he were totally new to the bridle. Lay the bridle over his face and reward him for letting it sit there; then use that trick to open his mouth, slide the bit in, let it stay a bit until he settles, then take it back out and reward him.
If he's especially tall like my boy is, and has learned that neat little trick where he puts his head up so high that you can't reach to put the bit in or work on his mouth, work on teaching him to put his head down -- pinch that bony ridge between his ears until he drops his head (even a little), release, then reward and repeat until he'll keep his head calmly on the ground.
Also, it couldn't hurt to have a vet check if he needs his teeth floated, make sure his bridle isn't too tight, try switching to a different bit (dependent upon the type of bit you're using, it could be too harsh and hurting his mouth) or making sure he's not getting his mouth yanked on a lot.
I've only had to deal with that for a couple horses. I've found that supporting the bit with your fingers until the bit passes their teeth gets them to accept the bit easier. I think that too many people let the bit hit the teeth. Especially to get them to open their mouth.
You could try using a rope and act like it's a bit for practice. This eliminates the metal from hitting their teeth.
How do you ask for him to open it? I put my thumb where the bit would be. Wiggle your thumb in there, without trying to put the bit in. Just only ask him to open. As soon as he does, take your hand away and rub his neck. When he opens it more easily and consistent, I would practice putting in the rope "bit".
Another trick is to have his head tipped toward you and down. That is a submissive position. It also gives you more control of his head. Posted via Mobile Device