My chickens happily free ranged for many years. Then housing developments went up all around me and the racoons, foxes, hawks and possums came looking for dinner and found it roosting in trees and running on my 3 acres.
After losing over 20 chickens I had to put up a large chain link pen and confine them to their predator proof hen houses at night....not an easy task. Had to clip some wings on persisitant escape artists and chase them down for many weeks.
Now they are all safe. I wish they could free range but it is no longer safe here. Sometimes I think about opening the run gate for a day but I don't know if they would all come back, so don't do it.