This is such a personal decision and a question of how much risk can you tolerate. Our hens LOVE roaming around the barns and house that we decided to let them do so despite having put up a 400 foot fence around their coop for them. Its also meant that I had to put up fences around my flower beds to protect them from the chickens but that's okay as we can actually see how happy they are roaming. We are also rural and see coyotes and other predators so we keep them in their enclosed area in the early morning and let them out afterwards. We are getting a rooster in 2 weeks which will hopefully be an added layer of protection / alert system. So far we have been lucky but fully realise that one day that luck may end - hopefully not but realistically.... We'll cross that bridge when we get there. Our neighbours also have free ranging chickens and haven't had issues - yet. If your chickens haven't tasted the freedom of roaming, keeping them enclosed in a large area will be easier.