How to Train the Hard-to-Bridle Horse
Bitting or Mouthing a Horse
Some people avoid traditional "bitting" or "mouthing" of young horses—but done correctly, it can help produce a horse that never has problems accepting the bit and bridle.
You start by putting just the bridle on with no bit. Some people also leave off the noseband at this stage and add it later. Then, you add a "mouthing" bit. A mouthing bit looks like a regular bit but has extra, loose pieces of metal called "keys" attached to it. Mouthing bits are often made with rubber or copper mouthpieces. Smear a bit of molasses or unsweetened applesauce on the bit when introducing it.
The horse is left standing in its own comfortable stall, with the bridle and bit in place for a few minutes, gradually increasing the time, although not to more than an hour or so. The horse should not be left this way for hours and should never be left completely unsupervised.
The next step is to introduce hand walking in the bridle; then, I would personally move to ground driving.
By introducing the bit this way, it becomes no big deal for the young horse.
Fixing the Problem
If your horse is already hard to bridle, however, then you need to address the problem.
First, understand that a horse may just have a hard-to-bridle day, like the mare I mentioned who was grieving for her friend and did not feel like working. If it is once in a while, then it probably just means your horse is in a bad mood that day, and while they should not be allowed to get away with it, it doesn't indicate a problem.
Eliminate Physical Reasons
If you do have a horse that is hard to bridle regularly, you need to first eliminate physical reasons. Make sure the bridle fits. If getting the headpiece over the ears is difficult, then the bridle is probably just a little bit too small. The bit should be fitted so that one crease (no more, no less) is visible in the horse's lips.
Check the horse's teeth, back, and ears. If the horse seems startled by the bridle, then you may also want to check his vision.
