Bird Flu Outbreak in Oregon Leads to Mass Euthanization of Poultry

In November 2023, Oregon’s commercial poultry farm businesses experienced the first avian (bird) influenza outbreak in the state. In response to the outbreak, the state’s Department of Agriculture reported that approximately 800,000 chickens were euthanized.¹

The two commercial poultry operations affected by bird flu were located in Linn and Marion counties in Oregon’s Willamette Valley. Two backyard operations in Marion and Deschutes counties were also affected. The Linn County business had 675,000 infected chickens and the Marion County business had 123,500 chickens.²

Oregon’s state veterinarian Ryan Scholz, DVM has quarantined the commercial operations to prevent the transportation of poultry or poultry products to or from those operations. He stated:

We don’t know why it happened. Sometimes it’s just a random, chance event. Most farms have strong biosecurity plans. We haven’t been focused too much on that piece yet. That will come. We’ve been focused on stopping the spread. Lots of wild ducks and geese migrating through the state are carrying the virus. This could happen any time domestic poultry are exposed to wild waterfowl, which is why biosecurity becomes so important.³

The nearly one million chickens were euthanized in Oregon using a controversial method that some animal advocacy groups have labeled as “extremely cruel.”⁴

Factory Farm Chickens Killed with High Heat and Shutting Down Ventilation

The chickens were killed using ventilation shutdown plus heat, or Ventilation Shutdown Plus, which kills birds by sealing off airflow in barns and increasing the heat to a high temperature until the chickens die of heatstroke, which can take up to several hours.⁵

The American Veterinary Medical Association (AVMA) reportedly allows the ventilation shutdown method as a last resort when other mass-killing methods are not practical, which was the case in Oregon. Dr. Scholz said that the Oregon’s Department of Agriculture and U.S. Department of Agriculture (USDA) authorized the poultry operations to use the ventilation shutdown method to euthanize the chickens because the state ran out of firefighting foam, which is typically sprayed on the birds to suffocate them—a method that considered a more humane.⁶

Dr. Scholz explained that an alternative method to euthanizing poultry is carbon dioxide poisoning; however, this method does not work efficiently for large chicken facilities and when there is a tight deadline for complying with USDA directives. He said:

It’s great on paper, but the amount of CO2 that it takes to fill a barn, let alone multiple barns, and the amount of prep that goes into it and the cost of that … it just has not been a viable option for very many situations, just because you can’t get that much CO₂. There’s always kind of a process of looking at what resources are available, what resources are an option and then coming up with a balance. The USDA guideline is that affected farms need to be depopulated within 48 hours of diagnosis, and so how do we do that given the resources we have in order to stop further spread of the disease.⁷

The ventilation shutdown method has also been used to cull poultry in Iowa, South Dakota, North Dakota and Utah.⁸

Forty-Seven States Have Been Affected by Avian Influenza

According to the USDA, 47 states have been affected by avian influenza since 2022 and as a result, 81.4 million birds have been culled in the United States.⁹ Washington had one commercial flock and 43 backyard flocks infected with avian influenza in nearly 1.02 million birds. California had 17 commercial flocks and 20 backyard flocks infected, with 836,000 birds euthanized.¹⁰

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