Fla. Stat. § 951.12

All persons confined in the county jail under sentence of a court may be worked on the roads of the county. In case the number of prisoners in any county at any time be less than five, the county commissioners of such county may arrange with the county commissioners of any other county for an exchange of prisoners. The county commissioners shall not be required to work the prisoners on the public roads when there is no contract between the counties as provided herein, nor when in their judgment the number of prisoners is insufficient to justify the employment of a correctional officer to work them.