Lofty dreams, you could cover the bottom and side with hardware cloth. It could be put on blocks or bricks or something like that. Poo would fall right through. I like the apron idea too. I like that better really. I like them to be able to scratch on the ground and pick at the grass and stuff.
The dogs are good deterrents to raccoons and possums, both of which we have in the woods behind us. I've seen coon tracks near my main coop, but not in my yard. I rarely have a problem with stray dogs coming down here and they would have a hard time getting in my back yard. There is hot wire on most of the fences because I have a menace of a pony that keeps trying to destroy my fences. Besides, if a stray dog showed up, my girls would let me know. The next one will be built much more secure because it's going to be out by the coop.
Henpecked, I'll have to remember that when I make the grow out hoop house: tarp between the stock panels and the welded wire.