We made a compost bin for our two dog's poop recently. We bought a plastic garbage can and then drilled holes in it it every two inches or so. Then we put some soil in and bought some worms for fishing and dumped them in too. We feed our pets a raw diet so they have dry crumbly poop it seems as if the worms are breaking it down though. This might help: https://www.wikihow.com/Compost-Dog-Poop