Ventilation shutdown (VSD) is a means to kill livestock by suffocation and heat stroke in which airways to the building in which the livestock are kept are cut off. It is used for mass killing — usually to prevent the spread of diseases such as avian influenza. Animal rights organizations have called the practice unethical. The addition of carbon dioxide or additional heat to the enclosure is known as ventilation shutdown plus (VSD+).[1][2][3][4][5]


The term ventilation shutdown appears to have originated in 2006 from the United Kingdom Department for Environment, Food and Rural Affairs. The practice was first permitted in the UK on the April 29th, 2006.[6] In the United States, approval to use ventilation shutdown was given in 2015.[7]

In 2020, supply chain disruptions from the COVID-19 pandemic led to many meat plant closures and in turn backup in slaughtering. In response, millions of US farm animals were killed via mass depopulation methods with ventilation shutdown often being chosen.[5][8]

The ongoing 2020-2022 H5N8 avian influenza outbreak has led to millions of birds being killed via ventilation shutdown. In March 2022, one of the world's largest egg farms, Rembrandt Enterprises, used ventilation shutdown to kill 5.3 million chickens after the appearance of an avian influenza case.[9]


The practice of ventilation shutdown has been called cruel by many animal welfare and animal right groups such as the Humane Society of the United States.[10] The process takes hours of high heat with one study putting the number between 1.5-3.75 hours for the egg industry.[11] Environmental temperatures as high as 170 °F have been recorded in facilities where VSD has been used. In known recordings of the practice for pigs, sustained screaming and signs of distress were observed.[5]

The widespread use of VSD is attributable by many, in part, due to the American Veterinary Medical Association (AVMA) publicly classifying ventilation shutdown's use as "acceptable under constrained circumstances". While unable to directly control if VSD is implemented, the AVMA's recommendations are often followed and used in determining legislation. Some people, such as the veterinarian Crystal Heath, have cited close between the meat industry and the AVMA as influencing their classification. There has been a campaign by organizations such the Veterinarians Against Ventilation Shutdown to get VSD reclassified as "not recommended" by the AVMA.[12]

See also


  1. ^ Bolotnikova, Marina (April 14, 2022). "Amid Bird Flu Outbreak, Meat Producers Seek "Ventilation Shutdown" for Mass Chicken Killing". The Intercept. Retrieved April 17, 2022.
  2. ^ "More than 2,900 Veterinary Professionals Call on AVMA to Prevent Brutal Ventilation Shutdown on Farms". ASPCA (American Society for the Prevention of Cruelty to Animals. December 15, 2020. Retrieved December 12, 2021.
  3. ^ "Ventilation shutdown: A humane depopulation method". Poultry World. August 9, 2017. Retrieved December 12, 2021.
    Eric Gingerich (2015). "What is Ventilation Shutdown (VSD/VSD+)?". Veterinarians Against Ventilation Shutdown. Retrieved December 12, 2021.
  4. ^ Malinda Larkin (August 25, 2021). "HOD recommends depopulation policy sent to expert panel for further consideration". JVMA News. American Veterinary Association. Retrieved December 12, 2021.
  5. ^ a b c Glenn Greenwald (May 29, 2020). "Hidden Video and Whistleblower Reveal Gruesome Mass-Extermination Method for Iowa Pigs Amid Pandemic". The Intercept. Retrieved December 12, 2021.
  6. ^ "Royal Society for the Prevention of Cruelty To Animals (RSPCA), R (on the application of) v The Secretary of State for Environment, Food and Rural Affairs [2008] EWHC 2321 (Admin) (07 October 2008)". Retrieved 2022-07-28.
  7. ^ Torrella, Kenny (2022-05-05). "The horrific bird flu that has wiped out 36 million chickens and turkeys, explained". Vox. Retrieved 2022-07-28.
  8. ^ "Millions of farm animals culled as US food supply chain chokes up". The Guardian. 2020-04-29. Retrieved 2022-07-28.
  9. ^ "US egg factory roasts alive 5.3m chickens in avian flu cull – then fires almost every worker". The Guardian. 2022-04-28. Retrieved 2022-07-28.
  10. ^ "More than 2,900 veterinary professionals and advocates call on AVMA to prevent brutal ventilation shutdown on farms". The Humane Society of the United States. Archived from the original on Jul 28, 2022. Retrieved 2022-07-28.
  11. ^ Eberle-Krish, Krista N.; Martin, Michael P.; Malheiros, Ramon D.; Shah, Sanjay B.; Livingston, Kimberly A.; Anderson, Kenneth E. (December 2018). "Evaluation of Ventilation Shutdown in a Multi-level Caged System". Journal of Applied Poultry Research. 27 (4): 555–563. doi:10.3382/japr/pfy036. ISSN 1056-6171.
  12. ^ Bolotnikova, Marina (2023-01-04). "The bitter civil war dividing American veterinarians". Vox. Retrieved 2023-07-02.