I live in an urban area but there are a few parks nearby and the foxes are everywhere, I could easily spot 5 or 6 in the space of 10mins at night. People feed the foxes (I had been known to do it myself sometimes) so they have very little fear of humans.
A few years ago when I had just the one dog (a collie cross called Tess) one fox actually went through Tess's legs to get at my cat Jasmine, who likes to come out with us for our last walk. I picked the cat up and the fox was actually jumping up at me to get at her. I tried to shoo it away but it just ignored me, it followed us all of the way home. Needless to say I never fed the foxes again.
Now Tess has been joined by another 2 dogs (a 2yr old westie called Angus and an 11mth old shih tzu called Archie) and the westie goes mad at the slightest whiff of a fox. He is a true terrier, if he ever caught one (we keep him on an extension lead so he doesn't get the chance) I have no doubt that he would tear it to shreds, and the foxes seem to know it. I very rarely even catch a glimpse of them now at night and my cat can safely come with us.