In my county there are many different zones i.e. northern agricultural, rural residential, town, business, industrial etc. etc. In EVERY zone agricultural use is allowed. When I went to the definition of agricultural it was very basic but basically covers plants and animals used for food. My chickens are for eggs, therefore they are agricultural use. Also, most states and counties have "Right to Farm" ordinances now. They are designed to protect the farmers but could also apply to the "backyard farmer". In my state farmers are protected against complaints about noises and smells that are usual and not harmful. Go online and read the ordinances yourself. The state you live in has their zoning code and then each county and/or town has adopted their own set of ordinances from the state code. Usually the local law rules over the state law.