Chickens. Chickens. Chickens.
We have 18 of them. They require minimal effort, if you have a rooster or two, they produce NEW chickens for you periodically, they eat bugs and table scraps, and even if you don't have a Rooster, they produce eggs. They are easy to kill and clean, the meat you get is tasty and fresh and it's the best thing we ever put into an old small shed.