When we lived in East Yorkshire, a stream formed the boundary at the bottom of our garden. We had four cats at the time, The matriarch, Parkin, was big and ready for anything, her sister Windle was scared of everything. Tom, the grey suffered with a bad leg and poor co-ordination as a result of a virus infection damaging his nervous system when he was a kitten, but he was a berserker if it came to a fight. Charlie, the little black cat, had all the fighting spirit of a teddy bear, could not have fought his way out of a paper bag.
One morning I heard Parkin give her "I'm going to kill you!" scream, so I went out to see what was causing the trouble. On the bank of the stream there were two ducks and a dozen ducklings. The four cats were standing shoulder to shoulder at the edge of the water, ears back, fur fluffed out and snarling.
The cats had a very protective attitude to the ducks, although they were wild mallards, not our livestock. They seemed to believe that if they lived in our garden and we fed them, they were part of the family.
When I looked across the stream there was a big dog-fox on the opposite bank, looking very interested in the ducks.
But there was no way he would think about taking four cats working together!
I was pretty sure it was a bluff on their part, but it was fascinating to see them actually acting as a 'pride' like that.
So maybe if your cats see the fox as part of the household, they may be OK, as long as the fox is able to agree to the deal.
Cheers
Dave