944.091 United States prisoners, board authorized.—The department is authorized upon request to board prisoners of the United States committed to their custody by any agency of the United States if such prisoners have less than 6 months remaining of their federal sentence, and if such prisoners have family relationships or job opportunities in this state, on a space-available basis only. Daily compensation for the board of such prisoners shall be paid at a rate to be mutually agreed upon by the department and the appropriate United States agency. Such compensation is to recover the total maintenance cost of such prisoners which shall be not less than the average cost per inmate per day for all inmates confined by the department.