765 ILCS 130/6

If any person neglect to repair or rebuild a division fence, or portion thereof, which he ought to maintain, any two fence viewers of the town or precinct, as the case may be, shall, on complaint by the party aggrieved, after giving due notice to each party, examine such fence, and if they deem the same to be insufficient, they shall so notify the delinquent party, and direct him to repair or rebuild the same within such time as they may deem reasonable.