I got two 2'x4'x1/2" MDF boards at HD in their cull wood pile, nothing was wrong with them other than a tiny spot where one had gotten wet but not at all warped. I read after buying them that the glue/resin used in manufacturing can give off harmful formaldehyde fumes. Can I still use this for my coop? They were intended for the floor of the coop, will tiling over them make them usable?