To help your horse overcome his trailering fears, you have to look at trailering from his perspective. Clinton Anderson explains the horse’s perspective.
As prey animals, with a flight or fight response, horses prefer to be in big open spaces where they can easily see predators approaching them and then be able to make a quick getaway. You’ll never see a prey animal having a rest in a tight, narrow space because if a predator came along, he’d be trapped. That’s why, as a general rule, horses don’t like trailers – they make them feel trapped and claustrophobic.
Not only do trailers make horses feel trapped and claustrophobic, but they’re also a scary object. Horses hate objects. What is an object? An object is anything that doesn’t live in your horse’s stall or pasture. Why is it no longer an object if it lives in your horse’s stall or pasture? Because if it lives in your horse’s stall or pasture, your horse sees it every day and gets desensitized to it. Horses especially hate objects that move and make a noise. A trailer does a little bit of everything. It’s an object, it moves, and it makes a noise when the horse walks up on it and as it’s traveling down the road.
If you put yourself in your horse’s shoes, trailering can be a traumatic experience, especially when the horse doesn’t understand that the trailer isn’t going to hurt him.