During the course of my life I have visited numerous zoos, some of them in different countries.
What I have noticed is that in a few of them I have actually been able to see foxes in caged environments.
I came to the conclusion that if it is possible to fence a fox in then it must also be possible to fence a fox out especially from a small chicken coop.
Maybe the saying should be, if you can’t afford the wire don’t have the chickens.
Unless you want to risk a fox attack that is.