The board shall adopt rules to provide for leaves of absence in the various classes of the classified service. Such rules shall provide for annual vacation and sick leaves with pay, and for special leaves with or without pay. They may provide for special extended leaves with or without pay or with reduced pay for employees disabled through injury or illness arising out of their employment. The right to regulate the time at which any employee may take an annual leave, or any other leave which is not beyond the control of the employee, shall be vested at all times in the appointing authority.
La. R.S. § 33:2557