I saw "nesting strips" for sale online. It's strips of corrugated cardboard. I made some myself and tried it out (got rid of all those shipping boxes left over from the holidays). I had my doubts since it's pretty stiff stuff, but it's working out pretty well. Anyone else out there use shredded corrugated cardboard? What would happen if I used it in the coop, maybe mixed with the pine shavings? What's the down side to using this stuff?