Wis. Stat. § 859.47: Payment of unfiled claims.

If a personal representative has in good faith paid unfiled claims against the estate, the payments may be allowed upon proof that they were just demands against the estate and that they were paid on or before the deadline for filing claims under s. 859.01, or at any time with the consent of the heirs or beneficiaries affected by the payment. Notice that application will be made for such allowance shall be given under s. 879.03. Payment shall be allowed on a proportional basis with other claims of the same class if the estate is insolvent.