I have one pair in a homemade cage that is 15inches High, 23inches long, and 15inches wide. It has soft shade cloth/mesh as a lid so they dont 'boink' up and hurt themselves, they have a self filling feeder & a flat dish for food, aswell as a water bowl, i have a plywood base covered with a good thickness of wood shavings, they have a small wood box as a hidey hole/nest box, I also have a small plastic tub filled with sand for them to 'dust bath' in.
My quails are outside 24/7 (its not nearly as cold here in Australia as elsewhere)
My buttons are happy and together (male&female) they hatch and raise all their own chicks before i move them into their own cage- simalar set up.
If anyone can suggest new ideas or improvements to my way of doing things, im happy to listen & learn.