I received a question on a previous post from a good friend Tom Theisen. “What is your approach for a mouthy, loose jawed horse?”
I don’t use a caveson very often, especially with a horse that has a problem holding the bit. I like teach the horse to hold onto the bit when possible. Before I explain, here is the Sally and Ernie story on learning from mistakes. Sally’s mother never let her into the kitchen when she was cooking so Sally wouldn’t get burned by any hot pans. Ernie’s mother told him to come into the kitchen and pull the pot of boiling water on his head. Which child will never touch boiling water? Obviously the answer is Ernie. He learned from his mistake.
When I start with a horse that likes to mouth the bridle or opens his mouth whenever pressure is applied to the bit I will get a bigger diameter bit. I like the ½ or ¾ inch sweet steel D ring smooth snaffle. I will adjust the bridle so there is a ¼ inch or so between the corner of the horse’s mouth and the bit. (No wrinkles) This will bounce around in the horse’s mouth unless they hold it with their tongue and cheeks. Basically they have to suck on the bit or hold onto the bit so it won’t move around in their mouth. I spend a lot of time making circles picking up the inside rein and when the horse bends his neck I let the rein loose. This will reinforce the horse to follow the pressure and when I let go they have to hold the bit or it will fall back down in their mouth, bounce around and become uncomfortable. By doing this the horse learns from his mistake of not holding the bit. The best part is I didn’t force him to do it. He wants to do it so he is more comfortable. He learned from a mistake.
The problem that may occur with non-western disciplines is the horse will usually drop his head to grab the bit when you let go. Great for western pleasure and reiners, but not great for hunters and English horses. It would give you a starting point to help the mouth problem though.
Thanks for the great question!