To follow up on chicken coop design article “A Newbie’s Perspective on Raising Chickens“, please consider:
My first coop had chicken wire all the way down to the ground. The possums would get one on each side at night, bounce the chickens from side to side (chickens are stupid at night) and then they would grab one through the wire and extrude them through the wire eating as they went. Within a month they were all gone. The whole thing was very disturbing.
My new coop has plywood sides with hardware cloth (1/2″ squares) on the upper part. As in the article, mine is closed in with plywood siding on three sides (1/2 way on the ends) and open at the top on the remaining sides with siding on the bottom part (all the way around) The closed in area has the nesting boxes. I did a closed in room behind the nesting boxes so I can access the boxes by lifting a small door in each box on the rear wall.
In the chicken run area, I used chicken wire at the top and roof but I used hardware cloth for the first two feet off the ground. Raccoons and possum are proficient climbers and will easily access the coop mentioned yesterday. There is also nothing to stop an owl or chicken hawk. We have panthers and I am sure an open top will not stop them. if you put a pressure treated wood piece at the bottom perimeter in the dirt as a nailer, it will be very difficult for an animal to dig in. I have not had any problem. I did use cypress fence lumber in the beginning and that has rotted out.
Additionally, I put a thin stainless floor over pressure treated plywood in my coop, sloped it slightly towards one wall, left an small 3/4″ gap under the wall bottom plate which is what the studs are fastened to (supported on short 3/4″ wood blocks every two feet) and I put a 3/4″ piece of wood in the gap (loose) to keep the snakes out. Removing the wood plug allows me to wash down the floor. If you taper the wood block and point the taper to the inside, it will funnel the waste out.
I am having a problem with something getting my larger birds during the day while they are free range, mainly the turkeys but the loss is manageable. A fake owl has stopped most of my chicken hawk losses during free range.
In my garden area next to the coop, the chicken wire buried in the ground has rusted away and this weekend project is to put another wood nailer on top of the first one to refasten the shorter wire.
And regarding the recent article on underground caches I must mention you need to put a hard secondary cap over a rubber cap or a plastic bucket that is buried at a shallow depth. This protective secondary cap can be made of thicker hard plastic, aluminum, steel, or pressure treated plywood. I have cows (and they would collapse a rubber cap or a bucket. A metal cap prevents that. Of course metal will show up with a metal detector which would be good for you if you are caching so that would be bad if you have unwanted people searching. With a cap, you can also use a probe to help relocate your items if the soil is not rocky. If you bury deep enough, you could use a dummy scrap metal piece above the cap to fool a coin shooting metal detector.