What works for us:
8'x4' house - linoleum on floor and up the wall several inches; topped with about a foot of pine shavings, which get stirred daily; topped with a few inches of straw that get refreshed every day or two and removed about weekly
attached to
8'x4' hardware cloth "veranda"; floor is 1/2 inch hardware cloth under sand/soil mix topped with 2 - 3 inches of sawdust which is fluffed and refreshed a couple of times a week. This is where the night time food and water are
attached to
a 16' x 10' day pen, bottom is coated chain link topped with a little soil and sawdust, topped with "mature" duck straw which gets turned every few days as it composts. This is topped off once or twice a week with a little fresh straw. Once a month or so in warm weather, the most composted material is removed from a section to go to the compost pile or garden
One section of the day pen is for the swim pan, 2'x3'x8", on top of pea gravel, on a 1% slope. Gets drained once or twice a day onto a sloped pea gravel section that drains into a small channel to the grape arbor.
Advantages:
worms come up through the composting duck straw - something to forage - free protein and amusement
worms and ducks turn straw into gorgeous compost
smell is earthy, not poopy
not much waste - materials end up in the garden one way or another
healthy environment for ducks - very little bumblefoot ever - no abraded feet
no pipe to get clogged with straw & fibers
I tried just sand in the veranda. Phew. No carbon to balance the nitrogen. Did not work for me. The soil is well drained, and the water would soak into the soil, but the stuff left behind stank - it was heavy nitrogen, and mostly anaerobic.