Miss. Code Ann. § 47-1-3

It is the imperative duty of the board of supervisors in each county in this state to require each convict sentenced to imprisonment in the county jail and the payment of a fine and costs, or to imprisonment and payment of costs, or to payment of fine and costs, to work out the sentence on the county convict farm or on the public roads or other public works of the county, or in a contiguous county, as herein provided. But any convict who is sentenced to the payment of a fine and costs and who pays such fine and costs shall thereby be relieved from working out such fine and costs, but the payment in full of such fine and costs shall not relieve such convict from working out the full time of his imprisonment as adjudged in his sentence. The board of supervisors of any county, however, may by an order spread upon its minutes, giving the reason therefor, and with the approval of the circuit judge of the district, discharge any aged or infirm convict upon his making an affidavit of his insolvency and inability to pay the fine and costs, and filing same with the clerk of the board of supervisors at any time after the expiration of his imprisonment.