OK. I am a conservationist (wolves) and I work with a number of scientists, anthropologists and biologists.
Foxes are not evil. They kill to eat and the reason why they may kill and not take the bodies is two-fold:
They react to species-specific behaviour (new phrase for instinct) when animals (such as chickens in a coop) make a noise. They kill.
They often bury the bodies - a cache - so that they can return to eat.
They very rarely attack anyone unless threatened...stories (like this fiction attempt from our OP) are ridiculous.
Foxes are not considered vermin but yes, if you feed them their populations will grow. So will the rat population.
I have chickens. It is MY responsibility to keep them safe and I am amazed how many people say 'Oh the fox got my chickens - I must have forgotten to put them to bed last night.'
How to deter a fox:
Get a male to pee around the garden - it has to be a male, dear feminists and yes, it annoys me too! This effectively scent-marks the garden.
Get a dog. They really don't like coming in a garden with a dog.
Get a sonic Foxwatch device. Not proven but I have two and have seen foxes avoiding it.
Never shoot a fox. Another will simply move into their territory...very quickly.
Foxes are not the devil and I really get tired of people with their hysteria. If there genuinely is a problem - not hearsay - then there are people who can help. I think a company called Fox Solutions are good.