Apparantly... I have it on good authority that if you get some hair from a tame local hairdresser and put it in a pop sock or cut down pair of tights and get a man to wee on it and then tie it on to a stick near the chickens it wards off foxes. Have to refresh the wee if it rains or every couple of weeks though.
a fox was getting in to the garden over the bottom fence so we bought this roll of bamboo/reed stuff and put it along the fence and since then we haven't had any cats in the garden!! presume the fox not been in either as the fence is undisturbed!
Our male Great Dane wees around the chicken pen everyday and it doesn't keep foxes or badgers away. (Perhaps they can tell he was the model for Scooby-Doo?).
The best deterrents are strong mesh fencing that is sunk at least one foot into the ground and either has a roof or is 10ft high with nothing nearby for a fox to climb on. Or line the base of the fence or the entire pen with slabs. Or use electric poultry netting. And if you free range, then sooner or later the fox will start picking the hens off one by one. We're having a good year, so far...