Mich. Comp. Laws § 750.144: Minor; boarding houses, licensing.

Sec. 144.

Licensed boarding homes for children-Any person who maintains a boarding home for children, unless licensed therefor by the state welfare commission, shall be guilty of a misdemeanor.

Any person who has in his custody or control for a longer period than 30 days, 1 or more children under the age of 15 years unattended by a parent or guardian, except children related to him by blood or marriage, for the purpose of providing such child or children with care, food and lodging, shall be deemed to maintain a boarding home for children: Provided, That nothing in this section shall be construed to apply to the legal guardian of the child.