If you're tired of buckling the poll strap, then use these 3/4-inch easy on-off halters. Designed specifically for minis, they come with an adjustable chin and a throat latch snap for your convenience. They're great for clipping, too; just unsnap and you can trim under your horse's jaw without taking the halter off.
Features:
Sizes (based on height at withers) (nose and poll measurements are approximate):