I just posted a response to the sand question in your other thread. I am a huge fan of using sand here in Oregon.
Oh, didn't mention in my other post: I used aggregate type sand, not beach sand. I have about 4-6 inches down. Very easy to rake around and keep clean. No need for dust bathing areas as the girls use it all.
Also, I was worried that it would be "sticky" when wet and stick to their feet, making a mess with the coop and eggs. I haven't seen that happening so that was also a plus.
I am building my run now it will all be covered with metal roof. I plan to put several inches of sand down in there, hopefully over a layer of rock, with treated wood base board and concrete blocks, it will be raised several inches above the outside ground level so any rain that blows in should drain and dry quickly