If you are wanting a bird that doesn't crow like roosters (making it possible to raise them in the city limits), produces 300+ eggs year round, takes up very little space and provides plenty of meat in a short amount of time then look no further than quail.
Jumbo Coturnix Quail has been bred to produce fertile eggs by the time they are 6-8 weeks old. At the same age the birds are ready to butcher at around a pound of live weight. They dress out at 75-80% their weight and their tiny feathers can be used in a wide array of crafts.
Once the hen begins laying it isn't uncommon for her to lay an egg a day for the first year of her life. Because of this, a flock of 30 quail (20 females and 10 males) can easily provide 120 eggs a week - the number of eggs a standard incubator can hold. With 30 quail and three incubators you can butcher 100 lbs of live quail every week for the freezer, or, with one incubator and 30 quail, 100 lbs of live quail and 200 eggs every three weeks.
Eggs
Five Jumbo Quail eggs is equivalent to one large chicken egg and taste almost identical, with a slightly stronger flavor. They are more cost effective to produce than chicken eggs, requiring two pounds of feed to produce a pound of eggs compared to three pounds of feed for a pound of eggs when dealing with chickens.
Meat
Quail meat is a delicacy with good reason. It is delicious, with a stronger flavor than chicken meat, and healthier for you. The meat is tender and can be cooked using practically any chicken recipe you prefer in addition to recipes that specifically call for quail meat. Since hens begin laying at such a young age, there is never a real concern about what to do with older birds - you can replace all of your stock every 12 weeks if you want.