If your garden is the site of excessive fouling then it could be that you are on the border of a territory and so the foxes feel the need to mark there regularly to reinforce their 'ownership'. Follow the steps below for general deterrence. 

Some find the noises made by foxes disturbing, largely because they sound like screaming or animals fighting. They tend to be rather less disturbing once they are understood. Most noise made by foxes will be between the months of September and January. In September, cubs leave their parents and seek their own territories. At this point there will be competition between individuals for space. This rarely leads to serious fights and two foxes can sometimes be seen standing on their hind legs, their front legs on each others shoulders, ears back and "cackling" at each other. This is nothing to be concerned about and this period will only last a short time. Then in December foxes mate and can then be heard calling to each other. Again this is nothing to be concerned about and will only last a short time. If foxes continue to make noise outside of these times, or the noise is excessive, then general deterrence as described below should help.  

We've owned rabbits and poultry ourselves so we know only too well how much they mean to their owners. We understand that to see a much loved pet be killed is extremely distressing. However, it is important to realise that foxes are only doing what comes naturally and not to overreact and anthropomorphise by accusing the fox of being malicious or evil. There are often accusations that foxes kill for fun. This is not true - only humans are guilty of this. The old story of a fox in a hen house killing more than it can eat is easily explained. A fox is stimulated to kill by the presence, sound, smell and movement of a prey animal. If there is one such animal it will kill one. If there are thirty it's instincts tell it to keep killing. Bear in mind that nowhere in nature would a prey species be congregated and confined in such a small area. The fox lacks the foresight to understand how many it can and can't eat. It is operating on a purely instinctive level.
I'm afraid it is our responsibility as pet owners to ensure that our animals are safe from predators. Make sure that they are housed in a secure run with strong mesh - chicken wire is not sufficient protection. Be sure to shut them into a secure, solid house (add a bolt or padlock) once it gets dark. By following these simple steps it is easy to keep potential prey animals safe from foxes. Remember - wildlife rescues manage to keep foxes in, so it must be possible to keep them out as well!
Cat owners are sometimes concerned as to whether their cats are at risk from foxes. There has never been a documented case of a fox killing a cat. Yes, foxes have been seen with dead cats in their mouths but it is more likely that they have picked up the body of an already dead cat from the road. The average weight of a fox is 5kg, exactly equal to the average cat. Foxes are omnivorous scroungers whose prey tends to be insects, amphibians and rodents. They are not equipped to tackle an animal of equal weight with a formidable set of claws. They're simply not that brave and there are far, far easier meals to be had!