Wis. Stat. § 88.04: General rules relating to signatures on petitions.

(1) Any person entitled to sign a petition to the court or the drainage board under this chapter may sign through an agent. The authority of the agent shall be in writing and shall be filed with the drainage board but need not be acknowledged, sealed or witnessed.

(2) If any minor or individual adjudicated incompetent owns land in a drainage district or proposed drainage district or proposed annex to a drainage district, the guardian or next of kin of the minor or individual may sign petitions under this chapter for and on behalf of the minor or incompetent.