Do hackamore bits hurt horses

Although many tack catalogs list Hackamores with the bits they are actually nosebands. The hackamore noseband can be made of several different things and that will affect their severity. A bicycle chain hackamore shouldn't be used by anyone. So long as the Hackamore is adjusted properly and used correctly then it's not going to be sever, but used in the wrong way and it can break a horses nasal bones.