The warden of each prison and all officers and employees of each prison and of the board of parole and all other public officials shall at all times cooperate with the board and shall furnish to the board, its officers and employees, information as may be necessary to enable it to perform its functions, and the wardens and other employees shall at all times give the members of the board, its officers and employees, free access to all prisoners confined in the prisons, workhouses and jails of the state.