Pre myxy most farms and estates had full time rabbit catchers,which used gin traps by the million which would of kept the fox levels very low.the fox will eat such a variety of food from beetles fruit small animals and birds and dead rotten meat which would kill a domestic dog if eaten the fox will thrive on,so I don't think the low levels of rabbits will bother fox numbers.much.when I started keepering poison was used like shake and vac,and now we have night sites and high powerd rifles and still the fox survives.and good luck to him tally ho.