Lethal industry-funded research studies methods used to gas, overheat and suffocate millions of farmed animals.

VSD is a controversial method of mass-killing farmed animals. In this barbaric practice, barns are sealed, airflow is cut off and the hundreds or even tens of thousands of animals inside slowly suffocate and die of heat stress or suffocation over extended periods of time. VSD is performed either on its own, or as what is referred to as VSD+ which adds heat or carbon dioxide to aid in killing the animals.

In the NCSU study, researchers subjected chickens for each phase of the experiment—plus additional birds for pilot phases—to VSD in various forms. The birds’ suffering was documented and, in some instances, recorded on video, in graphic detail. Each video depicts a single hen enclosed in a small box with a glass/plastic front panel for observation. 

As the boxes get hotter and the air inside more stagnant, and as carbon dioxide is sometimes added, the chickens writhe, gasp, pant, stagger and even throw themselves against the walls of their confinement in a desperate attempt to escape. Eventually the birds collapse and, finally, die from heat and suffocation.

In the footage, researchers are seen observing the suffering hens, taking notes and manipulating equipment as they sipped bottled water with oscillating fans cooling them.

The agriculture industry is using VSD today. Millions of animals are being killed across the country due to the most recent massive avian flu outbreak, with untold numbers being suffocated and overheated by the cruel method depicted in these videos. According to the USDA and state agriculture departments, VSD has been used in several of the recent avian flu “depopulations,” including one at a Tyson facility in Stoddard, Missouri where this cruel method was used to kill more than 300,000 chickens being raised for meat.

VSD came into the public consciousness at the height of the coronavirus pandemic after COVID-19 outbreaks at slaughterhouses and resulting meat supply chain back-ups caused producers, who could not send their animals to slaughter, to mass-kill them on the farm instead.

Animal Outlook, together with other animal protection groups, filed an emergency petition asking the USDA to prevent any COVID relief funds from being used to facilitate or compensate farms for using VSD. Nearly two years later, the USDA has yet to respond, but has all but denied the petition by disbursing relief funds indiscriminately.

The American Veterinary Medical Association’s (AVMA) “depopulation” guidelines later cited NCSU experiments and approved the use of VSD+ for chickens in “constrained circumstances.” In light of these videos, Animal Outlook wrote to the AVMA Panel on Depopulation urging them to list all methods of VSD as "Not Recommended."

It doesn’t take experiments to realize that slowly cooking to death and suffocating birds is cruel, yet the poultry industry funded university researchers to optimize this mass-killing method so large facilities could cheaply kill entire flocks on a routine basis. The research helped pave the way for the approval of VSD+ by the AVMA. We can now see this widespread inherent cruelty for what it really is, demand accountability under the law, and remove our support from this industry by refusing to buy animal products.