Complex sentence: In the United States and Canada, a frentera is rarely seen other than on some parade horses and for occasional use to support a bosal, where it is sometimes tied to the horse's forelock and is then referred to as a forelock hanger.
Split into simpler sentences: In the United States and Canada, a frentera is rarely seen other than on some parade horses. A frentera-like strap or leather thong used to support a bosal is tied to the horse's forelock and is called a forelock hanger.