Always use leather when securing a horse in the trailer. It can be a leather halter or just have a leather breakaway crown piece or fuse.? In a panic situation, or if the horse should back out of the trailer suddenly, the halter needs to break or the horse could get seriously hurt, especially with a neck injury.? In addition: 1. Always have at least one hole left on the crown piece above the buckle, since the most likely place it could break would be at the buckle hole, and you would still have a hole left to re-halter the horse. 2.? Keep a spare halter stored in your trailer.