I imagine it's a question of numbers--you must have many more fox in your area.
you know, I had never seen a fox, living or dead, in PA and DE, where I have lived most of my life, until about ten years ago-- suddenly, they were everywhere, though mostly stretched out between the white lines. I have always attributed it to the fact people, even farmers apparently, keep their dogs inside now, and you don't see them wandering around, like you used to when they formed a high percentage of roadkill.