I should finish up the 8x8 coop this week. I will start puting the tar paper and shingles down tomorrow. On the back wall we plan to hang the nest boxes outside the coop using the 16" on center 2x4 studs as the spacing for the boxes. Imagine having an open wall and building nest boxes hanging off the outside. I am having a hard time figuring out the actual material to use so that it is accessable from the outside and it is water proof. We have kicked the idea around to use a slanted top with shingles and a drop down door for the long side but there again, what material to use for it to hold up?