The Co-operative supermarket has come under fire from animal welfare activists after footage shows what is claimed to be malformed chickens at three of its supplier farms.

Campaign group Open Cages said it secretly took videos and photos at three Lincolnshire farms that supply the supermarket between August and November last year.

It said the footage shows birds looking deformed, injured and filthy – as well as workers emptying bags loaded with corpses into bins.

The activists claimed some birds were found near death, unable to eat or drink, while others had visibly untreated wounds.

They also claim one of the sites – Sheffield Farm – has been identified as identical to a farm featured in a video produced and promoted by Co-op on its website and in the press, showing healthy-looking chickens raised in clean, spacious conditions.

The group called the chickens in the footage “Frankenchickens” – a term used by activists to describe the type of birds that have been selectively bred to grow fast to produce more meat quickly resulting welfare concerns.

Connor Jackson, chief executive and co-founder of Open Cages, said: “Co-op’s loyal members and customers are being fed a deceptive and misleading fairy tale.

“These images prove that behind the carefully polished, ‘ethical’ image we all know, sick Frankenchickens are being condemned to lives of unnecessary pain, misery and stress on intensive mega farms.

“These birds simply grow too fast to lead any sort of decent life.”

The Co-op and the farm operators, PD Hook and H2S Ltd, said the sites have all recently been inspected by the Red Tractor Assurance Scheme – which inspects food standards – with no animal welfare issues identified.

Red Tractor also reviewed the footage and does not believe there is cause for concern or a re-audit of the farm is required.

It comes as the Co-op, which is jointly owned by millions of individual members and independent Co-operative societies, has been facing pressure over its chicken supply chain in recent years.

A row developed after a motion at the supermarket’s annual general meeting (AGM) in May this year asked for the Co-op board to “improve welfare standards for chickens and request the board to consider adopting the Better Chicken Commitment in full”.

The motion called for the supermarket to improve stock density – the amount of space birds have on farms – and adopt a slower growing breed that meets the RSPCA welfare protocol.

The Co-op said it supported the motion and it is now being actioned after members voted it through.

The supermarket has committed to improving the stock density, saying the measures will take effect in 2024.

Meanwhile, managing director Matt Hood told the AGM that he would not currently advocate adopting a slower growing breed due to the cost being around 30-35% more expensive.

He argued that the extra cost would likely be passed onto consumers amid the cost-of-living crisis, although the option remains open for the future.

A Co-op spokesperson said: “Ensuring the animals in our supply chain are looked after is a priority for us, and all our fresh chicken meets or exceeds Red Tractor or RSPCA Assured standards, supported by our new commitment, to improve and lower stocking density to give the chickens 20% more space and a healthier life.

“We are proud supporters of British Farming, allowing us to conveniently provide great quality, 100% British poultry for our members and customers.”

A Red Tractor spokesperson said: “Each of these three farms was subject to a regular independent inspection earlier this year and found to comply with Red Tractor core standards.

“Our team have viewed the footage but have not found evidence that supports further investigation.”

A spokesman for the farms said: “We maintain a zero-tolerance approach to any verifiable welfare non-compliances, although in this case we cannot confirm this footage, filmed a year ago, was taken inside our premises.

“However, for the record, the farms in question are all accredited and have been subject to multiple independent inspections as recently as June 2023.”