My largest embden gander survived a fox attack before as it's neck was so thick and tough to break and was bleeding at the breast area.
I have had many fox attacks and worst was year 2011 the year when everyday a fox came and and took a chicken lost over 80 chicken's that winter) later finding out it was actually four foxes that lurked around each day to get the chance (all my animal's are free range so it was hard to stop this straight away).
Anyway when I lost nearly all my chicken's no chicken went out of their coop so the fox turned on the ducks killing every single duck within the space of 2 Weeks, then it was the geese that got attacked and about ten were taken by the fox every other day so my geese didn't go in the fields anymore and were death scared and made the yard dirty and had no grass for weeks until one day I saw the geese finally going to the field and I was delighted as I watched and when they walked past the gate of the field a fox sprang and chased the flock in my yard! and I remember it got my embden female and the goose was fighting for its by biting and smacking the fox with it's wings as I let the dogs out (a boxer dog which is fast but is useless and the fox wanted to kill the goose you could see that but gave up as the dog got close,the goose was not injured but shocked and stressed as it was smacking the fox.
That was my worst year and never got chicken's or ducks since that winter.
Instead i got a German Shepherd cross British bull terrier dog (very good and alert) and I got guineafowl which are excellent fox alarms as they are quick and can fly and foxes never get them (except one last year my a fox kicked a guinea cock in a local shop,which gave the shop owner a heart attack).
Foxes are top preds and kill as much as possible or all and bringing only one carcass with them as they know that you will throw away the other carcasses somewhere for the fox so he can have a meal ever day.That's why they kill as much as possible and they will return to collect the other carcasses.