Hi my frinds hose does this and im always worried mine will copy! as far as i know from watching her horse collars dont really work,i know it looks and sounds nasty but i dont think it can do any physical harm can it? is he/she stabled a lot,i know its not always practical but i think its best to turn out as often as is possible,i know mine get frustrated being shut it,they stiffen up and get moody.In an ideal situation living permenantly out is best(apart from the mud/mud fever etc) saying that my friends horse windsucks on the fence posts in the field!