Even hauling a horse for several hours isn't going to be too harmful if the person driving has more brains than horsepower. If you drive at moderate speeds and don't swerve around or slam on the brakes then it won't stress your horse much. If you drive your crew cab deisel pick up with a 16 foot trailer behind like it's a Camaro then you will have a problem regardless of the kind of trailer you have.
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