A run is a fenced piece of land where chickens are allowed to wander. Using a run ensures that chickens will be safe and stay on the owner's property. The fencing for runs may be made of chicken wire or hardware cloth. It is advisable to completely enclose runs to protect against predators who may climb or dig under a fence such as cats and foxes enclosing the run also prevents aerial predators such as hawks from hunting your chickens.
Although free ranging is popular in rural areas it is advised and sometimes required to use a run in urban areas.