They’re not. They’re in family Procyonidae
Actually foxes aren’t smart at all. They breed fast so survive OK but there are loads of other animals out there that are smarter.
I saw a documentary on TV where they watched a fox family in the wild. Even the local rabbits could outsmart them and they were mostly starving.
I don’t have chickens so I enjoy having them around. Will try & find some of my pictures of them in our front yard.
I have chickens and have had a bunch killed by a fox. I shot at this little sob 4 times, never hit it. Then my boxer girl just missed getting the fox, she missed only because she hit a snowdrift. She missed the fox by inches, running herself into a wire fence in the process. Never had a problem since. I’ve seen foxes in the front yard, which isn’t fenced in, but never in the back yard, where my boxer rules. I figure a bullet whizzing by their head is pretty abstract, but a big, fast dog, with big teeth, that’s right in the DNA. I’ve also heard that you should never kill a fox or coyote that isn’t bothering your livestock. If your animals aren’t part of the cultural menu for that family of predators, they won’t bother you. If you kill or drive them off, another group might be a bigger problem.