Last week Daedalus was enlarging birds' eggs by adding an expanded ceramic shell. DREADCO biologists are now extending this idea. They recall the old trick of making an egg plastic with vinegar, and re-setting it inside a bottle. This suggests that the nucleation of an egg shell depends on special proteins which can be interfered with. DREADCO sees fowl as rather primitive egg-formers, ripe for improvement. Hens will accept almost any source of calcium for egg shells, even calcium carbide, which is lethal to them. Inside the hen, the hard shell is put on the egg last. It can be coloured brown, by a special dye fed to the birds. Hens even waste their resources on eggs if these are not fertilized.

There is, of course, a commercial target: the 20% of the British population who are vegetarians. As an egg develops, its proteins change to meat, and DREADCO wants to sell meaty vegetarian eggs. A plastic shell would let the chick inside develop almost to adulthood still unconscious. It never has to wake up, emerge or grow feathers. It can breathe, for an egg is porous, even more so if it is plastic and as it stretches. The egg could be partly immersed in a nutrient broth, or maybe injected with one, so that a small initial chick could get bigger.

So the DREADCO team hope to make their hens lay stretchable, plastic eggs. They see the brittle, rigid, calcium carbonate egg shell as an evolutionary step backwards. Birds are descended from reptiles, whose eggs are leathery. Genes from closely related reptiles might make birds' eggs plastic again. Alternatively, simply feeding the birds on calcium salts of plastic acids, such as polyacrylic or polymethacrylic, might do the trick. And if the resulting eggs are incomplete or somehow unviable, like the usual unfertilized eggs, this doesn't matter if the hens can be bred some other way.

Eggs as currently sold are very remote from life. The DREADCO team hope to produce a bigger but equally artificial plastic egg. The ideal product would contain not a bird, but the meat elements from which one might be constructed. The most committed vegetarian should accept in a plastic envelope meat that had never been conscious. But for how long should the egg be grown? Should a nutrient broth be injected? Ideally, the consumer will open the egg, dissect out the meaty, edible section and reject the rest, without even thinking of the bird that might have been: any more than we think this of an egg.