I live in a neighborhood and have very little yard, and my yard is not fenced. I want to put my chicken coop for my bantams on my back covered deck. I'll let the chickens out in a pen in the grass ocassionally, but my concern here is I don't want the wood of the deck being damaged. It will be damaged if poop/bedding/water sit on it. So what can I cover the deck with that will protect the wood and be safe to put bedding and chickens on top of? I tried a tarp for this exact thing at my last house, but somehow water collected under the tarp, and so when the pen and tarp were removed, the wood was mildewed and stained. I don't want that to happen again. Any ideas?