I'm very rural, so not much help there, but my coop is next to one of my horse pastures. It's fenced with 2"x4" wire horse fencing with hot tape on top, about 4.5 to 5 ft tall. The birds don't fly over it (nearly never!) but can scoot under, as I left a 6" gap at the base. On the lot line, I've got 4ft. goat fencing (4"x4") with hot tape, same height. If you select chicken breeds carefully, avoiding the really active fliers, That will help too. In town the het tape may not be legal, but it also keeps predators from climbing over! Mary