I have a 4 year old Quarter horse/thoroughbred cross who (we were told) was trained well enough for an advanced beginner. We were also told by the owner that she rode him in a hackmore bridle. When we tried a hackmore on him, he has no idea what he's doing as far as commands. I even had a trainer come check him out. My neighbor had been working on him and it takes a bit of fighting, but he will take the bit for her and seems to know his commands when she works him with a bitted bridle.
My son and I have been trying to work with him as well but no matter what we try, we cannot get him to take the bit.
There are many different kinds of hackamore bridles, some more communicative than others. I would suggest that you contact the former owner to find out exactly which hackamore that the horse was ridden in. Also, riding styles vary and your horse may be confused because every single person rides differently.
If you choose to ride your horse in the bridle, here are a few exercises to work on: 1. Teach your horse to lower his head. Begin with your hand behind his ears on his poll, apply slight downward pressure, the moment he drops his head, even a millimeter, release the pressure by removing your hand. Work on this until he will willingly drop his head almost to the ground. Be patient and remember to reward him by removing your hand and this lesson will come easy.
2. Teach him to open his mouth. He needs to learn to open his mouth without putting the bit in. While he is haltered, gently place your left thumb in the corner of the left side of his mouth, when he opens it, remove your thumb and pet him. It is my guess that he has not been accustomed to the bit and this exercise will cause him to be more willing to accept it. Repeat this exercise until he is no longer apprehensive about opening his mouth. This will also make worming him easier.
3.Now combine these two lessons with the bridle. Ask him to lower his head, holding the bridle carefully by the browband and the bit in your left hand, pull the browband up over his face, ask him to open his mouth and carefully insert the bit without banging on his teeth, now, point his right ear forward and place the headstall behind it, followed by the left ear, buckle your throatlatch and you are ready to go! Pet him generously so he knows it was a job well done.
Tip: When removing the bridle, ask him to lower his head, then open his mouth and the bit should gently slide out without banging his teeth.
Thank You and Happy Trails!