Waitrose has staked a claim for the highest welfare standards on supermarket chicken. From September, the stocking density of its Select Farm Chicken will be 10% lower than the industry standard in an effort to raise the bar in animal welfare.

The retailer says it is the only major supermarket to set a low maximum stocking density of 30kg/sq m for all its whole, own-brand chickens, and claims it is the lowest level of any major supermarket, excluding free range and organic. It now complies with the RSPCA's Freedom Foods certification of no more than 14 medium-sized birds per sq m.

Waitrose is so confident the regime will improve standards that it is selling whole birds with their hocks on and clearly visible, to satisfy shoppers they did not suffer from hock burn.

A widely watched Channel Four Despatches documentary last year found 82% of supermarket birds suffered from hock burn - which is a sign of intensive production in unsanitary conditions.