I wonder about that, too. Between the garden and now sprouting seeds for them again, they get lots of healthy greens.I've thought about sod, but wonder if it's got any chemicals in it, fertilizer or bug killer. I let my kids out of the run for about an hour the other day. I got nervous that I wouldn't be able to keep them away from a few ant hills I poisoned so we lured them back into the run with watermelon rinds......LOL