I installed a screen under the roost then used a piece of plexiglass as the poop board under the screen. I found out two things when fooling around. First is that the poop washes of the plexiglass better then anything I have tried hands down. The second thing was by total accident. I didn't have the right size of holes in the screen in the yard at the time so I temporary installed a screen with 1/4" x 1/4" holes. The poo just stayed on top of the screen and didn't fall through the screen. What I learned is that when the poo is on the screen it dries right away because it gets air all around it and there is no smell but when the poo hits the floor it stays wet and sticks to the floor. Now this is where the wet poo smell comes from. So I sized my screen so that the poo hits the screen, dries then shrinks and falls to the poop board as a dry powder. No smell and the poop board doesn't have any poo stuck to it. :) If there is any poo that doesn't fall through the screen the chickens push it though when walking on the screen. For the most part there is no poo inside the coop it is all contained on the other side of the screen.