Like blast said rabbits, if there is no feed avalible any fruits and veggies will do, if their not avalible then thats what the rabbits are for. Also consider pigeons, and doves most cities that won't let you keep chickens will let you keep pigeons and dove. Eggs are good to eat if a bit small, and they provide everything a chicken does.
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Depend on yourself, help those who are not able, and teach those that are.