Visit constructions sites and ask builders if you can get some of the scrapwood. They hire someone to haul it off when finished. Some landfills have this type of waste dumped in an area away from other garbage and let people get some for a small fee. Anything from pallets to old cedar fence boards are better options than those flimsy prefabs sold in the stores. Taking the time now to build a decent coop will save heartaches and money later. Some owners have made some clever and goodlooking coops from recycled materials.