The farm I volunteer at uses grazing muzzles for their overweight horses. The one, a small Arab, was extremely fat..she looked pregnant. About a month after using muzzles on the overweight horses, they look absolutely AMAZING. Just the right weight and they are calmer.
These 5 horses give lessons to about 23 kids each week, but usually at the walk/trot. They get grain everyday (unnecessarily in my opinion) and go out all night long.
I would advise a muzzle. Just make sure it’s not too tight, or he will get sores, and not too loose that he can lose it. Check often to make sure its not rubbing him. And introduce it slowly, some horses can be silly about it.
I love Clinton Anderson!!!!