Animal welfare activists will hold a demonstration at Morrisons in Devizes on Saturday – calling for the supermarket to remove “Frankenchickens” from sale.

Campaigners dressed in Morrisons butcher uniforms will stage a silent protest at the stores, brandishing placards revealing disturbing images of intensively-farmed chickens which they say are genetically engineered to grow unnaturally big, unnaturally fast and which are slaughtered after an average of 35 days.

The protest is being mounted by the animal welfare charities Open Cages and The Humane League UK.

Connor Jackson, the founder of Open Cages, said: “We will be demanding of Morrisons the removal of all Frankenchickens from its shelves.

"A silent protest will reveal shocking images from the supermarket’s chicken farms.

“We are saying that any animal which is sold for meat should not have suffered in its life.

"These birds are reared indoors and they have been bred by a process of selective breeding to grow 400 per cent faster than is natural, some of them become deformed and are unable to use their legs.

"Their average lifespan is 35 days, spent indoors. So they are killed before they are barely six weeks’ old.

“This protest come eight months after Open Cages revealed footage of chickens deformed and dying in agony on crowded farms supplying Morrisons’ welfare-assured ‘Butcher’s on Market Street’ meat label.

“Instead of following the lead of hundreds of other companies in pledging to phase out the controversial practices, Morrisons recently launched a small range of chicken reared to higher welfare standards. We criticise this as a cheap gesture that does nothing to help the millions of chickens that remain in the intensive conditions.”

But Morrisons has rejected the claim that it does not care about its chickens.

A Morrisons spokeswoman said: "We care deeply about animal welfare. All our regular chicken is raised to above Red Tractor standards; we are also the only retailer in Europe to ask our fresh chicken suppliers to require chicken to be born into the barn in which it will be raised by 2025.

“Eighty per cent of our fresh chicken meets this standard already.

"We also actively monitor for any malpractice in our supply chain; we will never tolerate it or look the other way and if we ever find it, we will act swiftly and decisively."

The Devizes demo is one of 21 protests that the animal activists will be holding outside Morrison stores across the UK, at 12-1pm on Saturday.