Michigan exempts breastfeeding from its public nudity statute. Michigan also has a law that requires courts to consider whether a child is nursing in determining parenting time in family law cases

750.335a
(3) A mother’s breastfeeding of a child or expressing breast milk does not constitute indecent or obscene conduct under subsection (1) regardless of whether or not her areola or nipple is visible during or incidental to the breastfeeding or expressing of breast milk.

MCLS § 722.27a, Child Custody Act of 1970

§ 722.27a. Parenting time.
(7) The court may consider the following factors when determining the frequency, duration, and type of parenting time to be granted: …
(b) Whether the child is a nursing child less than 6 months of age, or less than 1 year of age if the child receives substantial nutrition through nursing.