Prisoners are in jail not to have some time off from society and eat three squares a day while watching cable TV. They are in prison to pay a price for the crimes they have committed. Hard labor should be part of their price in an effort to Force them away from ever committing crimes again.
We so often hear of the escalating costs of keeping people imprisoned to the Government. Although there is a worry that turning incarceration into a business could happen I think that a safe middle ground would be to harness some of the kinetic energy of the prisoners to at least power the prison.
Prisoners forced to undertake hard labor like this are unlikely to benefit from such experiences and become rehabilitated. It is far better to encourage them to take on a form of work or education that is commensurate with their abilities, enabling them to make a valuable contribution to society and hopefully preparing them for a successful and crime-free future.
Our society should not use forced prison labor. Just because something was done in the "olden days," does not mean that we should be continuing the practice today. Prisons should be reformed so that non-violent prisoners can be rehabilitated. Prisoners should not be used like slave labor, but instead should be rehabilitated to re-enter society someday.