Millions of birds have been destroyed in the Central Valley's commercial poultry industry as a result of an outbreak of avian flu. Photo by Grace Mooney on unsplash

California’s poultry and dairy industries are being slammed by rampant bird flu infections that seem to be on the same viral trajectory. The spread of new infection happens daily and the Central Valley is ground zero.

According to a U.S. Department of Agriculture report released Thursday, an outbreak of highly pathogenic avian influenza (HPAI), or bird flu, was confirmed in a flock of 1.02 million commercial laying hens in Kern County on Nov. 20. The news follows an earlier find at another Kern County egg ranch this month resulting in the destruction of 2.1 million birds.

An Arizona egg ranch was confirmed on Nov. 13, and now has reported the death of 790,700 hens. That detection was made in Pinal County, just south of Phoenix.

USDA now says Thursday that HPAI was found in a commercial meat duck flock in Marin County on Nov. 30, with no details released yet on the size of the flock.

With these new flock infections, 28 poultry ranches in California have been impacted with the loss of 7.7 million birds.

The surge in cases has been centered in the Central Valley, including Kings, Tulare and Fresno counties, with four ranches in Kings County hit and the loss of nearly 900,000 birds.

USDA also announced Nov 12 that avian flu hit two Fresno County poultry ranches, one a broiler ranch for chickens resulting in the killing of 237,700 birds and a turkey ranch requiring the destruction of 34,800 toms.

Then on Nov. 14, USDA added three more poultry ranches affected, including one in Merced County —a turkey ranch with the loss of 53,200 birds — and another one in Fresno County.

The news follows recent reports about avian flu spreading to Kings County poultry ranches last week, resulting in the loss of over half a million birds.

On Monday, USDA reported new finds including in California with six new commercial flocks hit by HPAI bird flu, and British Columbia with 14 new cases, while Utah and Arizona each had one. The virus appears to be rampant in the Central Valley, with the virus found in two commercial meat turkey flocks in Fresno County this week involving 17,700 and 39,600 birds, a commercial broiler ranch in Fresno County with 259,000 birds, and two commercial broiler flocks in Kings County involving 279,300 and 53,300 birds. Also reported, a commercial broiler flock in San Joaquin County involving 29,100 birds.

Only days before Thanksgiving and the start of the holiday baking season, Central Valley’s poultry ranches are losing millions of birds including a huge number of egg laying hens, broiler ranch chickens and turkeys, with reports of new finds every few days.

USDA says California eggs prices have nearly doubled in the past month.

The virus is carried by migratory birds along the Pacific Flyway who visit the Valley this time of year, bringing avian flu for a ride from British Columbia to Kern County. One of the state’s largest egg ranches was hit, located not far from the Kern Wildlife Refuge and in the heart of dairy country, suggesting the proximity and rampant increase in the virus in both cows and chickens may be no coincidence.

More dairies too

The increase in commercial poultry farm infections is matched by the spread of bird flu among dairy cows, with 336 dairies in the state now impacted as of Nov. 19. The count seems to balloon every day in reports from the USDA. Just a few months ago there was no virus reported.

The two livestock industries that cluster their animals in confined facilities are often just down the road from each other in the Central Valley. The Valley poultry industry has been on a similar viral timeline to the dairy farms coinciding with the annual bird migration. 

Vaccine needed?

In an editorial in trade publication egg-news.com titled “APHIS Needs a New Approach to Control HPAI,” they recommend that USDA adopt vaccination as a disease control strategy for bird flu, with promising results from clinical trials. In May 2023, the US authorized the vaccination of California condors against a type of avian flu in California.

Also, the USDA has approved field trials to test vaccines that could prevent dairy cows from getting the H5N1 strain of bird flu.

The USDA approved the first field trials for the vaccine in September. The USDA’s Center of Veterinary Biologics (CVB) is overseeing the trials.

Poultry are already vaccinated for Newcastle disease.