I agree about using dirt. I’ve been researching sand and now I’m trying it out. I’m in there every day so it’s not a lot of work to scoop and remove. It’s not dusty and it doesn’t get muddy because because there is nothing to make mud out of. Hopefully I’m not violating any forum rules here...
I have a dirt (sand) run. Easy to keep. Sand is about 4 inches deep. Sand dries the droppings quickly and is less prone to mold, bacteria, lice, etc. I bought 3 yards of sand at a local landscape supply business and did the coop and run in sand.