Not all predators come from the sky, a raccoon, cat, dog , fox can easily make it over a 4 ft. fence like it was nothing - unless you have a top wire of electric fencing. That will just slow them down a bit.
If you clip wings you take away a chickens best chance for escape from predators. They will never win even one to one combat. Otherwise they will hide as best they can until preds nose them out.
The best way to keep chickens where you want them is a sturdy run with some type of covering which will also keep hawks out. Or you could train a livestock guardian dog to watch over them.
Even bold roosters will not win against four footed predators.