Supermarkets which boast of only selling eggs from free-range hens are buying pheasants and partridges reared in “cruel and environmentally damaging” cages, animal welfare activists have claimed.

Marks & Spencer (M&S), Waitrose and Sainsbury’s have been accused of double standards over the treatment of game birds they sell as meat.

Rights group Animal Aid contacted all supermarkets to ask whether they bought from farms that caged the breeding birds.

Crowding in cages causes high rates of injury and premature death and many birds are fitted with restrictive face masks to limit damage caused by stressed birds attacking one another, according to game shooting opponents.

Sainsbury’s had confirmed to Animal Aid that the partridges it buys are caged, the activist group said. Waitrose said its birds were not caged but “penned in pairs”, which the rights group said “raises some alarm bells”.

Animal Aid said M&S had “dodged our question 11 times in 18 months, and we are still awaiting an answer”.

Shocking conditions on rabbit farm in Europe Show all 15 1 /15 Shocking conditions on rabbit farm in Europe Shocking conditions on rabbit farm in Europe A rabbit lies at the bottom of a cage, surrounded by feces Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbit cages hover above excrement on breeding farm Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbit in a breeding cage Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Baby rabbit born on industrial breeding farm Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits in breeding cages Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits in breeding cages Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Baby rabbits born on industrial breeding farm Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Spray painted rabbit confined in a breeding cage Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits in breeding cages Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Excrement below rabbit cages on industrial farm Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbit with face injury Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits and young in breeding cages Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits in breeding cages Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Rabbits in cages hover above excrement on breeding farm Spain, 2013 Jo-Anne McArthur / Animal Equality Shocking conditions on rabbit farm in Europe Dead rabbits piled and bagged in a bin Spain, 2013 Jo-Anne McArthur / Animal Equality

The group claims cages fundamentally breach the government’s code of practice for game birds, which states they must have accommodation that fulfils their natural behaviours.

Caged birds cannot fly, roam, roost, dustbathe, wing-flap or regulate their own temperature.

In an email seen by The Independent, an inspector at the Animal and Plant Health Agency admitted that cages thwart birds’ natural behaviour.

Sainsbury’s, Waitrose and M&S all state they only stock free-rage eggs.

Sainsbury’s website says: “We care about the hens laying our eggs. That’s why we only stock eggs from 100 per cent British and cage-free hens.”

Every year 43 million captive-reared pheasants and nine million red-legged partridges are released to be shot – numbers that have risen sharply since the 1980s.

Wild Justice, a group led by television naturalist Chris Packham, says game birds released into the countryside for Britain’s £2bn shooting industry destroy native flora and fauna by eating plants, small birds and mammals, and the lead ammunition they are shot with accumulates in the countryside, poisoning wildlife.

Campaigners say only six per cent of the birds reared make it to the food chain through licensed game-processing plants as demand for shooting them far outstrips demand for their meat. Dead pheasants have been found dumped in pits, but estate owners says most birds are taken home by shooters or sold to pubs and butchers.

A parliamentary motion calling for a ban on barren cages, signed by 121 MPs before the election, says that “a large number of the breeding birds are confined for the whole of their productive lives in unnatural, unpleasant, crowded metal battery units, known in industry circles as raised laying cages”.

It adds that these units “cause the birds to suffer high levels of injury and premature death”.

Wild Justice has threatened to challenge the government in court over the effect on British wildlife of releasing millions of birds at the same time, prompting ministers to announce a review.

Game birds may be shot only in the open season, which runs through the winter, but the meat may also be frozen and sold all year round.

Packham said: “The spectacle of pheasants and partridges in overcrowded cages makes my stomach turn. The potential damage to biodiversity that occurs when millions of these birds are released needs immediate and independent assessment. Come on, supermarkets! You can’t boast about cage-free eggs and then be party to selling game birds reared in cages.”

In 2017 during an investigation into a Warwickshire game farm, partridges and pheasants were filmed in battery cages, with activists claiming many were stressed and in extremely poor condition. An Animal Aid spokeswoman said: “We have plenty of evidence of suffering – dead birds, feather-pecked birds, bloody birds, those wearing spectacles and bits, saddles and pads over injuries.”

In 2015, The Independent revealed photographs of pheasants being heaved into a “stink pit” on a private Berkshire shooting estate.

In email exchanges between M&S and Animal Aid, customer service staff said game chicks were reared in purpose-built shelters with access to outdoor runs. The parent birds had breeding pens with areas for the birds to choose to be inside or outdoors, M&S said.

Animal Aid responded by saying that those pens sounded exactly like enriched cages.

Fiona Pereira, of Animal Aid, said: “Caging a wild bird is utterly unjustifiable, and yet there are thousands of pheasants and partridges locked in cages, many of them injured, and all of them distressed.

“This is not even about food production; this is so people can shoot down their offspring for sport. How could any supermarket support such cruelty?”

Asked by The Independent to comment, Sainsbury’s and Waitrose both referred to a statement from Andrew Opie, of the British Retail Consortium, saying: “Animal welfare is extremely important to our members who comply with all standards. In this case, these are defined by the game bird industry and are tailored to the welfare requirement of those birds.

“Members are aware of how important animal welfare is to their consumers, and are in constant conversations with their suppliers to ensure the best practices are in place.”