My horse has only been trailered in a stock trailer and is always led out head first (she's 10). She was recently hauled by a friend who tried to get her to back out. She freaked and would back up until she couldn't feel the ground beneath her foot. She would step forward again and wouldn't go any farther. We did this for awhile then gave up and walked her out head first. I would like to buy my own trailer but only a two horse that she would have to back out of. What is the best way to teach a horse to back out of a step down trailer without them ******** and getting injured.