is this program covering the expiry date of the stock items?
No, whatever Manager does with inventory (stock) is written in the guides. It does not monitor FIFO inventory management.
In particular, manager considers all units of any given inventory item to be indistinguishable from one another and identical. You can use custom fields to add expiry dates for individual inventory items on transaction forms, but Manager will not do anything with that information except display it. The program will not alert you that items in your inventory are past their expiration date.