The wood is free and unique, plus you don’t have to get nails out. We should note here that if you want your birdhouse to have a front porch, you can make the bottom piece two or three inches longer than the birdhouse. Subtle colors on the outside are alright. I have been told to avoid pallet wood as some has been treated with arsenic, but do not know this to be a fact in all cases, just be aware of the possibility.