It is unlawful for an owner of a potentially dangerous dog or dangerous dog to permit the dog to be outside the proper enclosure unless the dog is muzzled and restrained by a substantial chain or leash and under physical restraint of a responsible person. The muzzle shall be made in a manner that will not cause injury to the dog or interfere with its vision or respiration, but shall prevent it from biting any person or animal. (Ord. 2100, 2005)