I use the Deep litter method in my Coop, no dropping board---don't see why anyone would use a dropping board. I only need to clean out the deep litter/poo compost in the spring when I want it for the garden. I then add lawnmower clippings, pine cones, needles, etc all summer long to build it back up. If I didn't clean it out in the spring, it would probably last a couple years or more since I occasionally turn it over with a spading fork or toss in scratch to have the chickens do it for me. It rarely mats up unless I have too many chickens in the coop, then you have to fork it up more often.The mulch gradually shrinks down over time.