Chicken farmers are under fire. 2008 looks like being an uncomfortable year for Britain's poultry producers after the RSPCA took out full-page advertisements in a number of newspapers yesterday to launch a campaign for a ban on the sale of factory-farmed birds.

The campaign is timed to co-incide with a series of programmes on Channel 4 entitled The Big Food Fight, which promise to expose the "hideous reality" of animal production. It is fronted by the celebrity chefs Jamie Oliver and Hugh Fearnley-Whittingstall.

The RSPCA is urging supermarkets to phase out the sale of all but free-range and organic birds by 2010, and has asked customers to sign its petition calling for an end to the practice of confining birds in a dimly-lit space the size of an A4 sheet of paper, and cramming them with grain to secure maximum growth in the shortest possible time.

Chickens comprise more than 90 per cent of the animals farmed for food in the UK and the way they are raised is unquestionably a disgrace. Just five per cent of the 855 million birds consumed each year are free-range or organic. It would take a cold heart and an iron disposition to argue that the remaining 95 per cent should not enjoy similar conditions.

Yet the effect, were all chickens raised in "free-range" conditions, would be to double or triple the price. What impact would that have? For households on modest incomes, a chicken provides a nutritious meal, a good source of protein and has the great advantage of being cheap. A switch to free-range birds would mean many of these families would go without rather than pay the higher price.

Banning the sale of cheap chicken would have a disproportionate impact on the poor and less well off, who are those most in need of improved nutrition. Helping the chickens harms the humans. Yet the RSPCA could avoid this dilemma if, instead of targeting chickens, it had the courage of its convictions and campaigned for a reduction in meat-eating of all kinds.

The benefits for the animals are obvious. If we ate less meat, less often, we could afford to pay more for it. Farmers raising fewer animals and selling them at a higher price could provide them with better conditions. If meat became a treat, rather than a routine part of every meal, consumers would demand better quality, which would dictate a better growing environment. Improved taste has a far better chance of persuading consumers to switch from the standard product to the organic variety than charity-generated appeals to their conscience.

A campaign for a reduction in meat-eating would have other health and environmental benefits, while avoiding the discriminatory impact of a rise in the price of one type of meat chicken. We are eating 50 per cent more meat than in the 1960s and global consumption is forecast to double by 2050. The largest study of the link between diet and health, published by the World Cancer Research Fund in November, concluded that animal flesh occupies too big a place in the typical Western diet. Our current level of meat consumption cannot in any case be sustained in the face of growing demand from newly-affluent consumers in China, India and other parts of the rapidly developing world.

It takes 8kg of grain to produce 1kg of beef, and large tracts of forest have been cleared for grazing land. Each of Britain's 10 million cows produces more greenhouse gases in the form of methane per day than a Land Rover Freelander on an average day's drive of 33 miles. Giving up meat could have as big an impact on climate change as giving up flying.

The sensible response to these developments is not to abandon meat altogether but to think more like a vegetarian not a lentil-chomping obsessive but one who uses meat sparingly and perhaps cheats occasionally with a bacon buttie or chicken curry. In many countries, meat is regarded as a relish, with the bulk of the meal coming from carbohydrates or vegetables. It is a case of "meat as a treat".

But the RSPCA is not ready to take on the wider issues. A spokeswoman said yesterday that there were other organisations campaigning for vegetarianism and it was content to leave them to it. She added: "Our concern is with animal welfare and animal health."

This is a missed opportunity. The country is primed to confront the bigger issues of health, the environment and animal welfare. The RSPCA and the other animal charities should join forces with food campaigners and cancer organisations to change the way we look after the land, the animals, our health and the planet. It would be a bigger challenge but it promises far greater rewards than putting a few chicken farmers on the run.

j.laurance@independent.co.uk