Clint and I were told we couldn't put a chicken wire bottom on the rabbit tractor because the rabbits would not be able to get to the grass through the 1 inch holes. We did it anyway because we know we have foxes and coyotes around. I think you can see from this picture that our rabbits were able to eat through the holes with no problem. They certainly ate down the grass! We are using a 16 x 8 movable pen for 6 rabbits. We move it twice a week with dollies (aka hand trucks). We also feed hay, pellets, fruit off our trees, edible branches we prune, scraps from the house and edible weeds from the garden. Not only can the rabbits eat the grass, but they are secure from predators which might dig under. We are able to put this pen right up to the edge of our woods. If you are going to keep rabbits on the ground to cut down feed costs, you will need to check on them daily and move them frequently. Eating grass exposes them to more parasites than the hay, so we have ours on a strict deworming rotation using herbs, ACV, and some vermicide drugs.