What conditions are they in? The standard wire-bottomed, low cage is stressful for quail, especially if they are surrounded by wire. They are ground birds who enjoy cover, and like to hide, so a wire cage is really really hard on them. A sandbox or two goes a long way to helping with this problem. It gives them a place to retreat that doesn't feel like it's up high (because of the solid bottom), and high sides that feels like cover. Also, they enjoy digging in the sand, and it's comfortable to them. They'll also lay their eggs in there which keeps the eggs cleaner & easier to collect.
The won't generally go into an enclosed box, so hide boxes are wasted on them. They like to see but not BE seen, so give them opportunities to get into a hiding place that is open on at least two sides to see out. This is true for the sandboxes too--give them two high sides (to prevent excessive waste of sand) and two low sides--for ease getting in and out, and for visibility.
Finally, for extra happy quail, give them things to do. They like to dig in sandboxes, dig in dirt, and peck through weeds. I used to grab several handfuls of weeds and toss in their cage when I had quail on wire (mine are on dirt at ground level now), and they loved it. They'd come to the doors waiting for me every day.