Well to be honest iev never been a victim of a fox attack so iev never taken too many precautions not to say my run is weak its not they very secured theres no way for them to dig under, force their way through in any way but they're 100% free range they're out all day with very little overwatch from me.
The foxes they used come around alot even before i started keeping chickens and now recently for the past few months i haven't seen them at all, I've seen then around and iev gotten comfortable hope it doesn't bite me in the back