This is why horses might benefit from chiropractic adjustment. Envision the curvature of the spine from head to tail and the muscles that attach and support it. Think what is going on in the pelvic area here.
From: Moseman's Illustrated Catalog of Horse Furnishing's and Goods
Example of a Cart Saddle. The Tug Chain is like a sliding back band and slides through a channel running over the back. These were used on cart horse that pulled very heavy loads. Click on the illustration for a larger view.
Training people and horses for competitive and recreational carriage driving, 35 miles east of Albany, NY in the beautiful Berkshire Hills of Massachusetts. Lessons by appointment and offering carriage driving clinics worldwide