I have a friend who has kept Quail for years. He has them in a hardware cloth pen off the ground. It is only about a foot tall and is on legs about 3' high. The other dimentions are about 2'X 6'. There is a plywood top on hinges to cover the cage. The hardware cloth is 1/2" on the sides and it also covers the top (under the plywood). There are two openings in the top cloth to allow you to reach in without allowing them to escape. They are also on a 1/4" hardware cloth bottom because he had a problem with raccoon trying to pull the little ones through the bottom of the 1/2".
His breeding cages are a little taller but smaller in other dimentions.
I use a single height flight cage made for finches it is about 18 inches tall and 18 deep and 30 long. I have one pair in here and they are spoiled. you could divide this cage and hold 2 pair if you block their view of the other pair. i places fake leaves on the underside of the top wires so they think they are under a bush and they do not popcorn unless they are really frightened and then they hit the leaves so not so bad.