Michigan Compiled Laws, Chapter 287. Animal Industry § 287.262

Sec. 2. It shall be unlawful for any person to own any dog 6 months old or over, unless the dog is licensed as hereinafter provided, or to own any dog 6 months old or over that does not at all times wear a collar with a tag approved by the director of agriculture, attached as hereinafter provided, except when engaged in lawful hunting accompanied by its owner or custodian; or for any owner of any female dog to permit the female dog to go beyond the premises of such owner when she is in heat, unless the female dog is held properly in leash; or for any person except the owner or authorized agent, to remove any license tag from a dog; or for any owner to allow any dog, except working dogs such as leader dogs, guard dogs, farm dogs, hunting dogs, and other such dogs, when accompanied by their owner or his authorized agent, while actively engaged in activities for which such dogs are trained, to stray unless held properly in leash.