Here's why:
* Different species: Dogs, cats, and foxes are all in the *Canidae* family (dogs), *Felidae* family (cats), and *Vulpes* genus (foxes), respectively. While they share some common ancestry, they have evolved separately for a long time and are now distinct species.
* Chromosome number: The number of chromosomes in a species determines the genetic makeup of an organism. Dogs, cats, and foxes have different numbers of chromosomes, making interbreeding impossible.
Even if they could mate, it would be highly unethical and likely result in offspring with severe health issues.
It's important to remember that breeding animals should be done responsibly, and interspecies breeding is not only scientifically impossible but also morally questionable.