I am building a new coop to replace the 5 smaller ones I have. New coop size will be 8x14 with a salt box roof. The base frame will be made out of 2x6 pressure treated lumber. I plan on using the concrete deck blocks to keep it off the dirt directly. I worry about moisture under the coop since the only place I can put it is on the downhill side of the yard. What should I use under the coop to promote drainage and not cause sinking of the blocks? Sand? Pea gravel? River rock? I have the long walls built and primed and painted to make assembly faster. (need to take pics) One thing I am wanting to discourage is the neighborhood cats trying to make a home under the coop so I will be skirting the coop itself with 1/4 inch hardware cloth. (Hoping it will help keep mice out from under too.) The 8' wide side will be facing north and the run will be on the west to help cut down on wind blowing in the coop. The run will have a roof as well. Huge project since I have to tear down all the existing coops and runs to get it done. While I build the coop the chickens will have a temporary shelter in the existing run and be confined there. While I build the run they will be stuck in the new coop. (cannot let them run the yard due to hawks and foxes) Thinking this is going to be a drag for them while it is going on. Fast assembly will be very important. Will take some pics of the walls today. Oh and it will house 20 hens and the run size will be 16 x 17.