Mont. Code § 81-4-509
A person claiming an abandoned horse or horses as provided in 81-4-508 shall, within 5 days after serving the notice provided for in 81-4-508 or within a further time that the board of county commissioners allows, upon good cause shown, submit to the board proof of ownership and shall deposit with the board the amount of any unpaid taxes and penalties that may be assessed against the horse or horses, together with a $100 roundup fee. The board shall decide all cases in preference to all other matters coming before it and at the earliest possible moment. If the claim is allowed, the roundup supervisor in charge of the roundup must immediately be notified of the decision and the supervisor shall deliver the horse or horses to the owner upon payment of any amount due from the owner for the estimated cost of keeping and feeding the horse or horses. The deposit made by the owner of taxes, penalties, and the roundup fee must be delivered by the board to the county treasurer. If the board denies the claim of ownership, it shall notify the person in charge of the roundup of its decision and the horse or horses as to which the claim is denied must be offered for sale at the earliest convenient session of the sales being held under the roundup. If the horses are not sold, they must be destroyed or otherwise disposed of as though no claim had been presented.
§ 81-4-509, MCA