Wow, that is an older picture before Hurricane Sandy forced my reinforcements.
Here is a better picture showing the lower 2 feet of the run wrapped in 1/2 hardware cloth, which actually contains the larger pieces.
You can see the depth of the litter.
As it decomposes, the birds scratch it out, where I collect the finished compost.
The boards are necessary to attach the 2 feet of hardware cloth on the bottom sides, and 2x3 fencing on the sides, top, and skirt.
Great system, Ron!!! Using the fence to filter out large particles and the chickens to move the fine compost out of the run is just fantastic...sure does make it easier to collect the composted material.