Chickens a make noise, all the time. They poop FAR more then you think, they're are stupid and do stupid things. They get diseases, there are predators, they die, they can fly over fences
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I usually appreciate your comments but you're dead wrong about this subject.
In my block of SFH there are 4 people keeping chicken (myself included) and there is hardly any noise related to the chicken. The only noise they make is after they've laid an egg. No rooster allowed though.
If you keep the run dry (roof against rain and covered with absorbent things, such as straw), there is no smell at all from their poop, which anyway is not an issue.
Chicken are not stupid, especially if they live in decent conditions (not crowded, clean environment, fresh water, nutritious food, gentle handling etc). Some breeds are quite smart for a bird (Ameraucana comes to mind). Almost all will protect themselves from day predators (hawks etc), especially in a backyard context. At night, you keep the coop closed, so there's no risk.
If they're well fed, chicken will not be able to fly over a 8' fence once they're reaching adulthood (but maybe the bantam do).
As for diseases, they almost never get sick if properly cared for. Good food, enough room and clean coop/run go a long way in keeping the (vet.) doctor away.