I am getting my chicks tomorrow, 2 Australorps and 2 Buckeyes. We have decided to use our sons Pack n Play as a brooder since its old and he climbs out of it anyway. Any advice for what to line the bottom with? We have the piece that it comes with to place in the bottom, should I just use that and put the pine shavings directly on top of it, or sould I do a layer of cardboard or newspapers in between the bottom piece and the pine? Thanks!