I think you have the answer in your explanation.

"If you have back-up stock tucked away in the back or kept in a drawer – pull it out! Your customers will only buy what they can see (because how will they know you have something if you are trying to sell that stock from a closed drawer?) Like the saying goes, “out of sight, out of mind”. Check your back up stock and place as much possible out in your display. Full shelves and displays sell."

http://www.saramazur.com/challenged-by-the-economy-what-to-d...

"Face all items as you go. Facing means to make sure all the labels face forward and that all of the products are at the front of the shelves. If you don't have enough stock to fill the shelves, pull them all the way to the front so customers can easily see and access them."

http://www.ehow.com/how_2271040_stock-grocery-shelves.html