I lived 5 years within Eugene city limits in the Southwest hills with a neighbor that had chickens (& I think ducks). Not once in the 5 years were we ever disturbed by the chickens. The only time we could hear them is if we were in our backyard during the day. Also, we never smelled anything.

Also, fresh eggs every once in a while was a very welcome treat!!

Good luck "Chickens in the Yard"!