He walks into the trailer okay, he just doesn't want to stay in there. Finally the hauler removed the divider and I was able to get Brego in and turn him around.
It's weird, once he's turned around in the trailer and facing out the back it's as if his bolting instinct suddenly gets turned off. He just stands there patiently while the door is closed.
Horses yawn because they have something stuck in their mouth, like some hay between the teeth or something. That's why I asked him if he had something stuck in there in the video. It was probably the hay