The flooring shouldn't be made of only wood...the ducks and chickens will poop on it, spill water on it, and before you know it the wood floor will start rippling and need replacement. Found that out with my first coop. Cover the wood flooring with lineoleum or other type of water reflecting product. This also helps in cleaning. I just built a coop and run for 4 baby chicks and 3 ducklings I got this week....the run is 12' x 6' and the coop 4' x 6' with a lineoleum floor over wood. Plan to cover it with shavings plus straw in the nesting boxes. The underside of the coop, which is off the ground a few feet, has siding on two sides to keep the ducks out of the weather of rain, snow, etc. I have heard they will probably build a nest of their own outside the coop, so this is why I enclosed an area underneath. Am hoping they will join the chickens and go into the coop each evening. The flooring in the run has hardware cloth stapled to each side of the frame so the whole bottom is covered (to keep out critters), landscaping cloth layed over that so we won't have grass or weeds, then that is covered with several inches of pea gravel....dry on the surface even after a rain. For a 12' x 6' run I got 1 yard of pea gravel and actually have a bit too much. Hope this helps!