That's a good idea, but I think I will use a heavy duty plastic for the sides on the bottom. I can then roll it up and tie it at the top, sort of like a tent window. That would let the sunlight in. Yes, it will eventually crack, but I'll make another. Plastic is cheap. And as for the tarp getting ripped by the wind, it will be tight enough not to be able to flap. I am a master seamstress, and have no doubts as to the fit. Thanks for the input about the sun, though! I guess I was thinking if it was that windy, they would be up in the coop, anyway. Covering the bottom will also keep the snow from blowing in under the coop, so if they would like to come down and be in the bottom, they could. At least while I am shoveling a path for them in the winter...