I have 5 pullets in a fairly large outdoor run that surrounds their coop. The run is on a slope up against our house. Our soil is very rocky and hard to work with. So far I've just left the run as dirt. Smell isn't an issue at all, I think that it's large enough that the poop doesn't build up enough to smell bad before it breaks down. But I hadn't accounted for how much impact 5 chickens can have on their run! They've caused quite a bit of erosion. Their constant scratching has pushed a deep layer of dirt and rocks down to the bottom of the run, and the top was getting down to the rock. And the worst part is that EVERYTHING is coated in dust. I have solar paneled Nite Guards to try to keep predators away and I often have to go wipe off the solar panels because the dust is so thick. Also, the chickens themselves are constantly dusty! The brown dirt has tinted all of my birds a different color! I know they like to dust bathe, but this is a whole other level! Anyway, I've started adding rock terraces to the run so that the chickens can't pull all of the material down to the bottom, and now I'd like to add either sand or gravel. I want something that is safe, clean, and that my chickens will like. Any suggestions? I've heard many people liking sand, but I don't want it to be too dusty! Other people have said gravel, but I don't have a good concept of what size gravel I should be looking into. And are there issues with the chickens eating the sand or gravel? Any thoughts would be greatly appreciated!