With the need for more troops not less,... Leave would be difficult to obtain if not wounded or some kind of medical condition determined on an individual basis. Definately not an entire company.The time frame your looking at is important to clarify.The location at the time and there is always Murphy's law. All furloughs/leave were handled by the Provost Dept.and a passport would be issued by them and enforced locally by them.It is more complicated then that but, in general.Many men took what was known as "French leave" which was not official to tend crops and other personal business. Many cases if caught were treated as deserters and this practice was frowned upon in both Armies.Read: Rebel Watchdog,The Confederate States Army Provost Guard,Kenneth Radley