Our leghorns free range with two dogs in an urban neighborhood. We have secure block walls, no known predators. Dogs are totally chicken safe. One is missing. Has been missing for two hours, starting at early dusk. No experience with them flying our 8' high gates. Big question, can one live alone? We have three more arriving as chicks in a month. Will one 6 mo old chick be able to survive alone till our babies are old enough to provide a new community?