In 2020, outbreaks of this highly pathogenic disease, most commonly known as bird flu, slammed the poultry industry, fueled by the intensive conditions that dominate U.S. farming of chickens and turkeys. These outbreaks led to the culling (the killing of animals before they would have been slaughtered for human consumption) of millions of farmed birds with controversial methods like ventilation shutdown — essentially using heatstroke to kill animals en masse, a practice criticized by animal advocates and some concerned veterinarians. While birds suffered and consumers faced rising prices, the turkey industry’s profits rose by 21 percent in 2022 over the previous year despite a drop in production.

The USDA has now reported the first cases of avian flu on U.S. turkey farms since April, impacting 47,300 turkeys on a South Dakota farm and 141,800 turkeys in just one Utah operation. This week, news broke of 140,000 more affected in Minnesota. These outbreaks demonstrate the massive scale of factory farms — and push the number of birds culled due to influenza in recent years to the edge of 60 million. 

What’s worse is that experts believe that the time of year and the migration of wild birds will mean that this threat will only grow in the coming months, as South Dakota’s State Veterinarian, Beth Thompson, told ABC News.

Bird flu is not only extremely contagious among birds but also nearly 100 percent fatal, a grim reality that means that farms cull their entire flocks when an outbreak occurs.

All animals want to live, a simple truth that calls into question the slaughter of any animal as humane. When killing thousands of animals simultaneously, the methods used become even more cruel.

One such method is ventilation shutdown plus (VSD+), in which all ventilation to a shed is shut down to kill many animals at once via heatstroke. Steam, heat, or gas is pumped into the shed to hasten the process, but some animals have been found to suffer for long periods, and others may survive the initial cull. 

In a study published in December 2022 amid the rising use of heatstroke to cull pigs and birds, researchers wrote, “Non-lethal heat stress is widely acknowledged to be detrimental to animal welfare…and temperature-humidity conditions that are high enough to cause death also are accepted as causing severe suffering.” 

Sadly, the American Veterinary Medical Association has not condemned this practice it considers to be acceptable in “constrained circumstances,” demonstrating how differently our society — even those whose work is dedicated to caring for animals — views the animals we think of as food and those we think of as companions. Veterinarians opposed to VSD+ have likened the practice to “leaving a dog in a hot car” with all windows shut and the heat turned on “full blast.”

Factory farming has been framed as progress, an efficient way to feed the world’s unsustainble demand for animal products, especially in wealthy nations like the United States. Yet, bird flu offers an alarming example of the inefficiencies of our industrialized food system. The very nature of factory farms aids the disease’s hold on U.S. farms and wipes out millions of birds who suffer brutal mass deaths due to the enormous size of commercial flocks.

Flu vaccines for farmed birds are being tested in the U.S. and have already been used for many years in other nations, including China and Egypt. While this may prevent the needless culling of some birds, it fails to address the wider problem — factory farming itself. The practice of factory farming leaves animals and the public open to further health threats. While avian flu is considered unlikely to transmit widely in humans, over 50 percent of human cases of the H5N1 strain have been fatal, and the industrial farming of animals is widely believed to be a pandemic risk jeopardizing public health.

“Bird flu is not the first threat to animal or human health that has been fueled by factory farming, and public health experts warn that it almost certainly won’t be the last,” says Gene Baur, Co-Founder and President of Farm Sanctuary. 

According to the CDC, over 75 percent of new and emerging infectious diseases found in humans originate in animals. As we continue to raise and kill farm animals in the billions and encroach on wild habitats, we are playing with fire.

“Resorting to the cruel mass killing of animals as agribusiness scrambles to control outbreaks is not an answer,” says Baur. “Factory farms are a petri dish for emerging diseases and antibiotic-resistant pathogens. We must address the root cause of the problem if we are to take this growing threat seriously, and that means shifting towards a safer, more sustainable, and more compassionate plant-based food system.”