How often do you remove the poop from their run??? It's no different than keeping a few dogs in a fairly small yard; if you don't pick up the poop, it's gonna stink soon enough!
A lot of folks go with a few inches of commercial sand in their runs because it's so easy to rake/scoop out frequently. I actually snap one of those thin, latex medical gloves on and go around collecting poop every few days. If you find the right rake (thin, flexible, tightly packed tines), that would work too. Sprinkling the DE as Opa mentioned will help too, as it's a drying agent (will dry out the poop fairly well).
A lot of folks go with a few inches of commercial sand in their runs because it's so easy to rake/scoop out frequently. I actually snap one of those thin, latex medical gloves on and go around collecting poop every few days. If you find the right rake (thin, flexible, tightly packed tines), that would work too. Sprinkling the DE as Opa mentioned will help too, as it's a drying agent (will dry out the poop fairly well).