This is a follow up after using sand in my duck and chicken runs for a few months now. I live in Northeast Florida where it seldom ever freezes, we have hot humid summers and we get rain most every day during the summer. My runs are each 12' X 12', 4 ducks in one and 8 chickens in the other and neither one is covered or has a roof, they're open wire on the top and a 80% shade cloth. I put down commercial grade nursery fabric then 6" inches of coarse dredging sand so it is just like the sand on the beach.
After quite a few days of heat well over 90 degrees I found that the sand does not get hot to the touch. I suppose the shade cloth keeps it from getting hot. We have had rain just about everyday for the last few weeks, at least an inch at a time and a couple of times 3-4 inches, there has never been standing water. After it rains the first inch or two of the sand dries by the next morning (about 12 hours), then the rest within a few days if it doesn't rain again.
I clean the chickens run weekly by raking it out and sifting any poo, feathers and leftover cobs or melon rinds. If it has been rainy there isn't much poo, it washes it through the sand. I expected that this would be a problem, that it there would be a gross layer of waste between the sand and nursery fabric. After digging down there is nothing but sand, no smell that I have noticed so far.
On the ducks side the sand is working out pretty well. The ducks poo can't be raked up and sifted out, even if it has been dry for a few days. There are small areas in their run that they spend a lot of time where there are concentrated amounts of poo, like at the feeder, waterer and their favorite spot to lay in during the day. Those areas are where the sand tends to clump and pack down. I rake out their run once a week as well loosening up the compacted areas turning the sand. Again, there is no noticeable smell.
Overall I am very please with the sand. I know that by now without the sand I would have a muddy mess. My birds are all healthy so far, it is easy to clean, my chickens enjoy dust bathing in it, and it makes the overall appearance of the runs nice and tidy looking.