The growing pains of a selectively bred chicken

A plan to accelerate further the unnatural growth rate of broiler birds is condemned by campaign groups

Picture a six-year-old child weighing 286lb, or more than 20 stone (130kg). That, says a senior research scientist, is the reality of life for Britain's broiler chickens – and it is about to get substantially worse.

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Warning as chickens reared at faster rate

Leading article: Selective breeding is more worrying than GM food

Picture a six-year-old child weighing 286lb, or more than 20 stone (130kg). That, says a senior research scientist, is the reality of life for Britain's broiler chickens – and it is about to get substantially worse.

Think of a six-year-old with a body weight of an even more monstrous 24 stone and then imagine it trying to walk. Hideous and cruel for a child – but the near future for a broiler.

The cheap poultry we have got used to in every supermarket is produced so inexpensively at a high price in suffering. Unnaturally rapid growth rates, induced by selective breeding, have led to broiler chickens becoming massively too big for their own bodies and suffering wide-spread lameness and heart failure as a result.

Yet these growth rates are about to be increased still further by British poultry breeders. Chickens that, in 1976, were reaching just over 1kg in weight at the age of six weeks are now reaching 2.6kg in the same period – and encountering severe welfare problems because of it. They will soon be reaching 3kg at the same age.

Experimental strains of these 3kg birds have already been bred at centres in Scotland and Essex and, during the next five years, will become the stock for the "crop" of 820 million broiler chickens produced in Britain every year.

Animal welfare campaigners and academics say the new growth rates will lead to an increase in the massive welfare problems that have long been associated with broiler chicken production. The breeders flatly deny it, saying the new strains have been improved and will suffer fewer welfare problems, not more. They say that, in breeding birds with even higher growth rates, they are responding to the demands of their customers – chicken producers and supermarkets.

The new birds have been bred by Britain's two main poultry breeders, Ross Breeders of Newbridge, Midlothian, and Cobb Breeding of East Hanningfield near Chelmsford. Each company is now controlled by one of the two biggest poultry breeders in the world, both US-based – Ross by Aviagen Inc and Cobb by Cobb-Vantress, Inc. Between them, they have 80 per cent of the annual breeding market of 300 million birds.

The advent of their new chicken strains was disclosed two years ago in a paper written by four Ross scientists for a meeting of the British Society of Animal Science, entitled "The challenge of genetic change in the broiler chicken". They wrote: "Live weights at 42 days have more than doubled in the past 23 years (from 1050g to 2600g) and are projected to reach 3kg by 2007."

At the weekend, executives of both Ross and Cobb confirmed to The Independent that these 3kg birds have now been bred. They did not wish to talk on the record, other than to insist that these new birds would suffer fewer of the leg and heart problems suffered by their lighter, slower-growing predecessors, although they could not give figures to indicate the size of the projected improvement.

Animal welfare campaigners rejected their assertion. Abigail Hall of the RSPCA said: "Certainly the problems will get worse, and it's totally unacceptable. They should be paying a lot more attention to the health and welfare of the current birds and the last thing they should be doing is increasing the growth rate further. We want the search for faster growth rates stopped."

Joyce d'Silva of the campaign group Compassion in World Farming said: "It's an absolute scandal. Already, millions of chickens are lame for the last week or two of their lives and here's people like Ross Breeders making that situation even worse. It is completely unacceptable in a civilised society."

Academics also expressed concern. Donald Broom, a professor of animal welfare at the University of Cambridge, said: "I think most people would find this [the new growth rate] disturbing.There has been a general ethos in the industry that what is needed is faster growth and more efficient conversion of feed to poultry meat and that's the most important thing to do. But we have reached a point where there is a very substantial amount of damage to the birds. These [new] birds are going to suffer even more pain.

"We're in a situation now where people have to turn around and go in the opposite direction, and produce birds which will grow more slowly."

There is not doubt that current growth rates have produced very serious welfare problems for broiler chickens, which are kept for their six-week lives in darkened sheds, each one containing up to 50,000 birds.

The incidence of lameness and heart failure is disputed between the chicken industry and its critics but even the industry's own figures show that lameness, for example, affects millions of birds.

Lameness is measured by a "gait score" of one to five, with three and above meaning, in the words of Peter Bradnock, chief executive of the British Poultry Council, that "the bird's welfare is compromised".

A recent survey by the industry, still unpublished, indicates that a gait score of three and above was suffered by "only" about 2 per cent of birds, Mr Bradnock said. When it was put to him that this represented about 16 million chickens, he said: "Yes of course, it's a lot of birds and it is far too many. But the industry invested millions of pounds in the past few years in improving management."

Between 3 and 4 per cent of birds die from various causes before slaughter, the survey results show – that would represent between 25 and 32 million birds annually. Non-industry estimates of lameness and mortality are significantly higher, and the Government hopes to get a more balanced picture from its own survey next year.

The physical stresses that a broiler chicken currently endures can be visualised by the aforementioned comparison with a child, – suggested to The Independent late last week by a senior research scientist with huge experience of broiler chicken welfare problems.

Begin, he said, with what is natural – the wild ancestor of our domestic chicken, the red jungle fowl Gallus gallus of south-east Asia. This handsome bird of the forest floor reaches maturity at 18 weeks of age, when it weighs less than 1kg (2.2lb).

Compare that with a human being, reaching maturity at 18 years, and weighing, let us say, 50kg, or about eight stone (which might well be an underestimate).

By 1976, the domestic chicken was reaching 1kg in a third of the time, just six weeks rather than 18. So picture, for comparison, not an eighteen-year-old but a six-year-old child weighing eight stone. Just about imaginable, perhaps.

Now, though, because of the intensive selective breeding by the broiler industry in the past 25 years, the six-week-old chicken weighs 2.6kg. That's the equivalent of a six-year-old child weighing 2.6 times 50kg – 130kg, or more than 20 stone. And in the next few years, we will see in the supermarkets – unless it is stopped – broilers attaining fully 3kg in six weeks, the equivalent of a six-year-old weighing 150kg, or nearly 24 stone.

Elliot Morley, the Government's animal welfare minister, told The Independent."We think there are justified concerns, and there are legitimate questions for the breeders to answer. The present situation with regard to broiler welfare is not acceptable and it is surely more sensible to address this now than carry on with even more increased growth."

The Government was pressing for an EU directive on broiler welfare that might be drafted next year, Mr Morley said. Asked if the directive might cover calling a halt to growth rates, he said: "I think that's a legitimate issue that has to be taken into account."