They roamed, they clucked. They were very big chickens.

I NEVER thought I'd say this, but Jurassic Park has started to change my perception of things. Take eggs, for example. The eggs we normally get come in boxes from Paxfield Farm, on which is stamped: 'From hens allowed to roam on Wiltshire pasture'.

I think it's the word 'roam' that has started the rot. Roaming is what travellers do when they have to get material together for a book, or what herds of bison do when they have the whole of America to choose from for their holidays. More to the point, it's what dinosaurs do. Or, at least, what dinosaurs did. And now we are all being focused on dinosaurs again by Jurassic Park, I'm not surprised that I had the most lurid dream the other night.

Before I went to bed I was in the kitchen, and there my eyes must have fallen on the egg box and its message, because no sooner had I hit the pillow and drifted off than I was dreaming the most hectic adventure in full colour and Dolby sound . . .

SCENE: The primeval Wiltshire countryside, before it had become Wiltshire. The uplands stretch away, stark and stiff, with fringes of forest at the lower edges. At the edge of a primitive track there is a sign reading: 'Welcome to the Jurassic Era' and underneath, in smaller letters, 'Twinned with the Triassic Age'. There are three of us: me, Professor Snoddy and someone I don't recognise but who turns into Sylvester Stallone later on when we need him.

Snoddy: 'We have travelled back millions of years to prehistoric Wiltshire to see what monsters roamed the earth in those days.'

Me: 'But surely there never were dinosaurs in Wiltshire?'

Snoddy: 'I'm not talking about dinosaurs.'

Stallone: 'My God] Look] What the hell's that?

A mile away, round a hill, comes lumbering a chicken about 50 feet high. Every time it clucks, the ground shakes. Now and then it stops to pull a tree out of the ground and peck something off it.

Snoddy: 'Yes, gentlemen. Just what I expected to find. Giant chickens. Nobody would believe my theories, so I had to travel back in time to prove that hens once roamed the earth.'

Me: 'How did you know?'

Snoddy: 'From the remains I found.'

Me: 'Giant chicken bones?'

All this time the hen is coming closer and closer to us, covering the ground in enormous strides.

Snoddy: 'No. Giant eggshells.'

As he speaks, the chicken subsides on to the ground. Moments later it gives an earth-shattering squawk and leaps up, leaving behind an egg the size of a small saloon car. It spies a small stegosaurus trying to hide and, squawking furiously, goes to attack it. The stegosaurus puts up a spirited defence but it is no good, the huge hen pecks it to death.

Snoddy: 'Everyone kept saying that Wiltshire had a white rock formation because of chalk. Fools] Only I knew that it was compacted eggshell. But from where had the eggshell come? From giant chickens of course] They said I was mad] Do you think I'm mad?

Stallone: 'Nope. I think you're a genius. You've just discovered a cheap source of chicken dinners. This could make our fortune.'

Snoddy: 'The White Horse of Westbury] Pah] Have you ever looked at those white horses? They don't look like horses at all.'

Me: 'You mean - the White Chicken of Westbury?

Snoddy: 'And why not?'

Me: 'But surely, if there really were giant chickens they would have left some descendants. Or did they die out altogether?'

Snoddy: 'Not entirely. There are still parts of Wiltshire where they roam. Up on the downs from Warminster there are huge tracts of lands where the public is not allowed.

Me: 'I know. It's MoD land. They keep it for firing ranges and tank practice.'

Snoddy: 'Exactly] And what are they firing at? Giant chickens] But they want nobody to know this]'

Stallone: 'I've changed my mind. I think you are mad. My God - it's coming back]'

He's right. The giant chicken has heard us and is running our way. The last thing I remember is Stallone leaping out with an

AK-47, Professor Snoddy shouting 'Don't ruin the feathers with the bullets]' and me being woken up by the sound of the firing.

This dream is shortly to be turned into a major action picture: 'When Poultry Ruled the Earth'. All rights reserved.