It's a lot of work for a horse to keep standing in a trailer going down the road. It's better for your horse to just leave them comfortable in the trailer and let them stand still while you're stopped. I've trailered 8 hours at a time and only stopped for gas and to eat. I never unloaded them and they came out fine.
There's nothing like the Rockies in the springtime... Nothing like the freedom in the air... And there ain't nothing better than draggin calves to the fire and there's nothing like the smell of burning hair. -Brenn Hill