depends what quail you are thinking of keeping....
chinese being the smallest, italian jumbo the largest.
i have italian jumbo, japanese and californian.
most quail are ground dwelling, with the exception of claifornians and gambols.....so you will need some sort of ground cover for them.......preferably plants of some kind rather than a box structure.
quail fly straight up so you need a decent height to whatever you keep them in. mine are in cages 3feet high, 2 feet deep and 4 feet long.....each cage houses 2 hens and 1 cockbird. they are in a heated, lit shed in the winter months......i use one normal lightbulb to light up a shed 16 feet x 8, and the heating is by way of a halogen heater.
feeding is easy...chick crumbs up til 8 weeks old then straight on to layers. as a treat once or twice a week i also feed millet, hemp, sunflower kernals and any mix of finch seed available at the time. they also enjoy mealworms and grubs aswell as green stuffs.
it is true they are cannibalistic, especially if they are overcrowded. and the males are worse than the females. summer they go into aviaries. their call is inoffensive to neighbours if you have any.
if you plan on hatching any eggs you will need an incubator as they are not very good at hatching their own eggs.
hope that helps a little....