The purpose of the training is not just to have Chieftain to go easily in to the trailer, but to have him to feel calm and secure so he will travel safely.
At first Chieftain is really uncomfortable and a bit claustrophobic in the trailer. It’s important not to try to force him to remain in the trailer if he wants to get out. Always let the horse go out if he feel the need to, just follow him and as soon as he is outside, ask him to go back into the trailer. When I first ask him to follow me into the trailer, he tries. Then he feels uncertain, stops and starts moving backwards. I will just follow him out, and then ask him again. After a short while he will understand that staying in the trailer means resting and no pressure.
I didn’t drive him this very first time, but I started to get him used to the trailer moving, making noises and I closed the bar behind him. All the foundation work I’ve been doing with Chieftain has made it so easy to train him with the trailer. As you can see in theese films, he prefers to stay calm and listen even if he’s afraid and insecure.