I tried composting poop in a garbage can with drilled holes, it wasn't doing a lot so I added water and closed the lid. OMG my whole yard smelled like a sewage spill in just a few days.
Maybe sand is not the best solution in your situation. My coop/run is a little higher than the surrounding area and has a fair over hanging roof on all sides, even with severe rain we see only splats of rain inside. With dry sand, the poop dries and can be sifted out periodically.
You may consider adding dirt or other littler, move the flock out while you work and till it in?
But 2 inches of poop would be an awful job to deal with, good luck.
And get a mask or cloth to cover your nose and place a few drops of oil of clove on that - it will make the task a lot easier.