I'd use pine shavings or if you can find it (I have not been able to) there's a ground cover made of straw-like material and treated with soybean oil that is absolutely dust-free. Wish I could find it around here.
I am not sure where the sand idea came from. It gets dirty fast, and unless you have gravel under it, it does not drain well. But the biggest problem I see with it is that if the sun shines on it, it gets super-hot. Tried walking barefoot on hot sand? Chickens have the same experience. I'm not a beach girl and neither are my chickens!
You could just go with plain dirt, too. Can plant some edible ground cover on it and they'll have greens.
I think it dries out better than most other material (such as straw). The big factor is, it does not mold if it gets wet. Birds are very sensitive to mold. Keeping poultry is work, and part of that work is keeping their bedding fresh. If your run is covered, it should not get wet by weather/rain. That helps. You can use a deep litter method where you just keep adding material on top, mix it a bit to get the composting of the bottom (dirty) material going. I clean out my coop, throw it in the compost heap, add "stall clean" (or diatomateous earth) then put down clean bedding. I entirely clean the coop every couple months in winter (cold here). In summer I clean it entirely out about once a month, and "spot clean" places where it's dirtier.