Thanks everyone! My thoroughbred actually goes in a hackamore because she's almost uncontrollable in a bit. Today she kept her head up for most of the canter, but still put it down every once in a while. Any other advice?
I agree with the Wilkie but with 3 piece mouth.
There is a book called “Training the 3 day event horse and rider” by James Wofford and he’s extremely knowledgeable. He explains behavior like that as a “dry mouthed” horse and suggests for them to be put in a loose ring snaffle to help with the issue
A horse at my old barn used to do that. I personally think it was because he rode a lot of inexperienced jumpers and he got sick of the unnecessary polls and tugs. My advice is keep your confidence. If you have a plan and keep your horse on it strictly, it will eventually get tired or fighting back. Good luck!
My horse used to do the same thing and my other one throws his head too the horse that got heavy in the hand we just changed his bit to a bevel (wilkie) and he stopped but with my horse throwing his head he does it when he is tired or getting bored so maybe just try working on stamina and changing the exercises up a bit more but all horses are different 😊
Hope this helps