Just want to clarify -- is 1/2" hardware cloth too big for quail chicks, then? We should get 1/4" instead?
Here is how I would build the cage.
Assume final cage: 24x18x36".
Using 1/2" x 1" hardware cloth, 36" wide, cut
2 36x18
2 36x24
2 18x24
Use fine file or heavy duty sandpaper to remove the razor-sharp edges from the cut wire or buy a gallon of peroxide and several gross of band-aids.
Using zip wire ties, assemble the pieces into a box.
Cut out what ever size door opening(s) you want. For quail, they are usually put in the top. If you put the doors on the side, you will have to put the quail you catch back in the cage while you chase the ones that escaped while you were catching the one that you have to put back so that.............. Even when put on top, don't make it too big or you will have to put back...........
Cut the doors from the same material, making them 1 or 2 inches larger than the door opening. Attach them with wire ties as the hinges. To receive an "A" for "Neat & Tidy", orient the door 1/2"x1" openings the same as the cage material. If you don't, the quail will be traumatized and when they escape into the wild, their friends will laugh at them.
To make the latch, bend a coat-hanger wire, or preferably something a little springier as follows:
Starting at one end, at about 2", bend it 90 degrees.
At about another 2", bend it around a broom handle a couple of times.
At this point, the wire should still be sorta, kinda in a straight line, except for the tail from the first bend hanging down.
At about another 2", bend it 90 degrees the other way from the first 90.
This should make kind of a half swastika with a curly-que in the middle.
Then bend a hook on the end either to the right for a right-hand latch or to the left for a left-hand latch.
Cut off the extra.
John