Mich. Comp. Laws § 409.113

Sec. 13. (1) Each employer shall keep posted conspicuously in or about the premises at which a minor is employed, a printed copy of sections 10, 11, and 12 as furnished by the department. (2) Each employer shall keep in or about the premises at which a minor is employed, an adequate time record which shall state the number of hours worked by the minor each day of the week together with starting and ending times and other information the department of labor requires. The employer shall keep the record on file for not less than 1 year.