Made a sandbox out of scrap wood today. Took about an hour (what can I say--I'm not much of a carpenter, but I have good intentions, lol), and the quail love it. I had to design it to fit through the small front door, so it's not as big as I would have liked and only two can fit at a time. And there are always two in it--didn't even take them long to get over the "omg what is that thing and will it eat me"s. I mixed oyster shell in with the sand, and made a lip around the top to keep the sand in. I forgot that the sand itself would make it heavy, so they're definitely not tipping that thing over, even if the materials themselves were lightweight.
Thanks for the tips and ideas--it's working out great. We'll see if the sand stays mostly inside the box, but so far so good. Thank you!!