A treatment device and method are provided for shaping the neck of a horse. The device comprises an impermeable double-walled sheet made into a sleeve or hood which is proportioned to closely surround the neck of a horse, the sheet providing a space between the walls thereof. A hot air blower is provided and hot air is conducted from the blower into the space between the walls of the sheet at a temperature between about 100. degree. F. and about 175. degree. F. The neck of the horse is caused to sweat and to be shaped as desired.