Photos depicting long lines of killing boxes being marched to fur farms have caused shock and anger around Europe. The devices are being used to gas mink after more Covid outbreaks on fur factory farms in Denmark.

Danish veterinarians and farmers have begun slaughtering at least 2.5 million mink in northern Denmark, authorities have confirmed, after coronavirus was reported in at least 63 farms.

The Danish Veterinary and Food Administration is handling the culling of the infected animals while breeders who have non-infected animals on a farm within 8 kilometers (5 miles) of an infected farm must put them to sleep themselves, said Flemming Kure Marker of the government agency.

Campaign Director of Respect for Animals, Mark Glover, said: “This is shocking news and these images greatly distressing. It should be clear to all that keeping animals in tiny, cramped, barren cages – and in terrible conditions- creates an environment for diseases to spread rapidly.

“I’ve seen many awful scenes on fur farms during my decades of campaigning, with terribly high levels of early mortality . Now we have major coronavirus outbreaks among factory farmed mink across Europe and in Utah, USA.

“Fur factory farming is a disaster for animal welfare. It must be banned.”

Scientists are exploring how the mink got infected and the extent to which they spread it to people. Some may have received the virus from infected workers. Dutch authorities say some farm workers later caught the virus back from the animals.

In August, the Netherlands brought forward the mandatory end of mink farming by three years to 2021 amid a huge outbreak f coronavirus infections at fur farms.