Much rubbish has been written in recent weeks about how easy it is to protect free-range chickens from foxes. All you have to do, say the know-alls, is shut the birds up securely at night, and stop worrying.

Nonsense! Reynard is a determined and resourceful predator, and if the chickens really are free-range - on the loose, in the open, rather than confined to a big run - he will get some of them sooner or later. Never mind that we shut ours up with the greatest care every evening: still the numbers keep being whittled down.

Our fowl are particularly vulnerable, because we live on the side of a hill, separated from the wood above only by a couple of sloping grass fields. Foxes often sit in the open during the day, shamelessly fancying the selection of substantial dinners parading about below them. They have all the time in the world to choose their moment - and whenever they do pounce, it is sod's law that they get not one of our superfluous young cockerels, but a precious laying hen.

Luckily daylight attacks are at worst sporadic. We go for weeks without one, then suddenly get several in quick succession. One of the worst spates occurred not long before our daughter's wedding: I was sitting in the kitchen with the Rector, discussing details of the service, when I heard a tell-tale screech-up in the garden. "Sorry!" I cried. "Got to deal with a fox." Snatching up a rifle, I ran out, shot the raider - which sure enough had killed a chicken on the lawn - and returned to our discussion. The Rector, good man that he is, did not turn a hair.

Yet if daytime visits are intermittent, nocturnal patrols are unceasing. Whenever I kill a rat I leave it out in a field, secure in the knowledge that it will have gone by morning. If we want to dispose of meat that has gone off, or superannuated bones, they too go out, and vanish. From the faultless efficiency of the scavenger service, it is clear that sweepers come past every night.

Occasionally they make mistakes. When I found a quince dumped half way up the paddock, pitted by tooth-marks, I could only conclude that a fox had scrumped it out of the orchard and carried it some distance before deciding that the taste was not all it should be.

More often, though, the aim is all too accurate. Eggs left uncollected vanish overnight, and our most recent major casualty was a speckled hen, black and white, which took against roosting in the barn, and perched instead on a beam in an open-fronted shed. Night after night, just as it got dark, we caught her and transferred her to safety. Then one evening we forgot. At 1am we were woken by an awful death-screech, and in the morning there was only a trail of feathers to show where she had been carried off down the lane.

Fox-pressure being what it is, we were dismayed when our solitary Bramah - our champion hen, she of the furry feet - once again went broody, and opted to incubate a nest in the same open-fronted shed, on top of a stack of hay-bales. Twice before this year she had sat successfully, but both times she spent the 21 days of dangerous immobility inside a secure coop, coming out at intervals for food and drink.

This last time my wife made her a beautiful nest in the coop, but again and again she marched off to her preferred eminence. There she was, a literally sitting target, protected only by the fact that incubating birds lose most, if not all, of their scent.

The only reinforcement we could give her was a barrier of Renardine, the age-old stink-bomb, now available as an aerosol. I should not care to say what it is made of (and nor, apparently, do the manufacturers). The effect is of well-matured tiger's or wolf's piss. The can depicts cats, dogs, rabbits and so on fleeing in all directions, and I do not blame them, so devastating is the stench.

Whatever it is, it has done its stuff. The Bramah has survived, and hatched off safely. Her brood amounts to only a single yellow chick, but once again, she has triumphed against heavy odds.