While walking around your coop you might consider leaving some human scent as an off putting marker? If you're male, just urinate at the corners? If you're a female just sprinkle some from a bottle? Can't hurt and might give fox something to think about.
I fear once a predator has successfully found a meal at your place it will always be in the habit of coming back for that meal.
All you can do is secure your coop. Read the thread on designing a coop to prevent predation and make yours extra strong, using materials that no fox could ever claw...