Wis. Stat. § 103.23: Age minimum.

(1) Except as provided in sub. (2), a minor under 12 years of age shall not be employed or permitted to work at any time in any street trade.

(2) A minor under 12 years of age may work in a fund-raising sale for a nonprofit organization, a public school, a private school, or a tribal school under the following conditions:

(a) Each minor must give the nonprofit organization, public school, private school, or tribal school written approval from the minor’s parent or guardian.

(b) Each minor under 9 years of age or each group containing one or more minors under 9 years of age must be physically accompanied by a parent or a person at least 16 years of age.