I have a homemade chicken ark (not made by me) that seems to have been made following the Catawba Coop design pretty much exactly: http://catawbacoops.com/the-catawba-converticoop-chicken-coop-image-gallery.html My chickens are sometimes kept inside it and sometimes free-range. We are running into the issue of not always being able to be home to pull up the ramp at chicken bedtime. Since the ark has no bottom, I know I cannot leave the girls safely at night without pulling up the ramp, because critters could dig under. I would like to figure out a way that we can keep the ark movable while also making it possible to come home late occasionally. My thoughts are these: 1) Change out the field fence to hardware cloth and add some kind of removable bottom (not sure how to do this...maybe it would be better to put on a permanent bottom? Could it be field fence or chicken wire? Hardware cloth seems like it would completely disallow access to the ground when the girls are in the ark.) 2) Change the field fence to hardware cloth and place the ark on a concrete patio on evenings we will be out. This way nobody could dig under. I can't imagine anything smaller than a bear (no bears here!) could push the ark off the patio--it's very heavy. Thoughts? Do I actually need to change the field fence to hardware cloth? The disadvantage of doing that is that the kids love to feed the girls through the fence when they are in the ark.