I have two four and a half week old chicks. They are currently under a heat lamp in a big box. If it is warm enough outside, say 70-75 degrees, I let them run around in the backyard in recently constructed planter boxes. They have no dirt in them as of yet and are about 6'x6'x2' and make great little play pens for the chicks to get used to being outside. However, when I bring them in at night or on cold days when they stay in their box, they tear up the newspaper in their box worse than a nesting rat. Is there anything to recommend that may let them scratch without me having to clean out their entire box everyday?