Dr Marc Cooper, RSPCA farm animal scientist, said, "If people knew how the average chicken was treated before it ended up as their Sunday roast, they would probably be disgusted. Currently, some supermarkets are selling chicken meat for as little as £2 per kilo - this can be less than it costs to produce the bird. Selling chicken so cheaply doesn't provide farmers with enough money to enable or encourage them to rear their birds to standards the RSPCA finds acceptable.

"Everyone has a responsibility to ensure chickens are reared to high standards - the retailer, shopper and farmer. We are asking supermarkets to stop selling standard chicken and shoppers to stop buying it. Chicken labelled Freedom Food, free-range or organic is a better welfare alternative. We are asking shoppers to demonstrate to supermarkets that there is a demand for higher welfare chicken by signing our petition and by showing they are willing to pay a little bit more money for a bird that's had a better life."

The RSPCA hopes shoppers will insist on higher welfare chicken in the same way that more people than ever are shunning eggs from battery cages. Almost 38 per cent of eggs sold in the UK are now from non-caged hens as millions of shoppers protest against cruel battery farming of laying hens. But only about five per cent of meat chickens reared in the UK for meat are kept in higher welfare conditions.

Channel 4's Food Season starts on Monday 7 January 2008.