Chickens who escape from captivity in the New York area have a champion at http://www.bravebirds.org/.
This reminds me of a story I heard some years ago, about a bus driver who opened the door at a stop and a chicken hoped on to the bus. The driver kept her on board for the rest of her shift, and when no one claimed her, took her home.
It may be an urban myth, as it was told to me as 'This happened to a friend of mine,' but it could be true. Chickens are very resourceful and often bold in making their way in the world.
Historic breeds are known for their ability to forage and find their own food. It's a quality that doesn't manifest in show competition, but breeders who seek to maintain the characteristics of historic breeds select birds who are good foragers for their breeding pens.
This photo from the University of Wisconsin, http://www.uwex.edu/ces/animalscience/poultry/index.cfm, shows how chicken tractors can take advantage of this natural behavior. As the chickens clean up the insects and weed seeds in the area under the tractor, it can be moved to another location for them to start over. This kind of system makes chickens part of a sustainable system.