We built two of this coop with these instructions about 6 years ago and they are holding up great! They are quite heavy, which accounts for the sturdiness, but also makes them difficult to move; we had intended to move them twice a month throughout the summer but usually ended up moving them only 3 times. They tended to get busted up on the uneven ground when moving with the tractor. Also with no floor, we have had predators digging under. Any suggestions for making this more mobile?