Would the urine of an eight-year-old protect my chickens?

I was predicting in a recent column that the arrival of spring would be bad news for my poultry, and so it has turned out: two ducks, a fat, waddling Silver Appleyard called Doris and a graceful, elegant little call duck called Marina (the loyal partner of a still-surviving drake called Boris), have disappeared, almost certainly victims of a marauding fox in search of food for its new cubs. For a while I thought that the missing ducks might be sitting on eggs somewhere, but the belated discovery of a pile of feathers put an end to this hope. Now I am waiting gloomily for the fox to strike again, probably this time against my chickens, which can’t even hope to escape to the safety of the garden pond.

What, then, can I do to protect them? Keeping them in their coops all the time would work, I suppose, but I wouldn’t dream of it.