A row has broken out between the RSPCA and British Poultry Council over the extent to which British shoppers have changed their chicken purchasing habits.

An RSPCA poll this week claimed 73% of consumers were now buying higher-welfare chickens following Jamie Oliver and Hugh Fearnley-Whittingstall's Big Food Fight TV shows in January.

The poll also indicated that 27% of shoppers would be prepared to pay £2 extra for higher-welfare chicken and 22% would pay £3 more.

However the BPC described the RSPCA results as "misleading" and not reflective of what was happening in the marketplace. "The RSPCA's claims about a sudden amazing change in shoppers' behaviour based on its own survey are not borne out by consumers' actual buying," said BPC chief executive Peter Bradnock, adding that sales of free-range Red Tractor chickens had been rising before the programmes.

Bradnock said that while free-range chicken sales were a growing area of shoppers' buying preferences, these still only represented 6% of total chicken sales.

Also this week, Nielsen released details of a survey it carried out in the aftermath of the programmes, in which it asked respondents whether the shows had affected consumer attitudes. Almost three-quarters said they would change to free-range or organic as a result.

Some 42% of respondents expected retailers to drive the change to higher-welfare chickens. However 38% of respondents believed that while the programmes were informative, they would not be likely to influence most people's shopping.

Weekly value sales of organic chicken jumped 40% in the month following the programmes, from £1m per week to £1.4m per week, Nielsen said.

Increased demand for free-range, organic or higher-welfare chicken could lead to shortages in store, it predicted.