PETALUMA, Calif. — Last month, Mike Weber received the news every poultry farmer dreads: His chickens tested positive for bird flu.
Following government rules, Weber's company, Sunrise Farms, had to cull all of its laying hens — 550,000 birds — to prevent the disease from spreading to other farms in Sonoma County, north of San Francisco.
“It was a shock. We're all miserable as a result,” Weber said, standing in an empty chicken coop. “Petaluma is known as the egg basket of the world. To see that egg basket go up in flames is devastating.
A year after bird flu led to soaring egg prices and widespread shortages, a disease known as highly pathogenic avian influenza is wreaking havoc in California, having escaped an earlier wave of outbreaks that decimated poultry farms in the Midwest.
The highly contagious virus has devastated Sonoma County, where officials have declared a state of emergency. In the past two months, nearly a dozen commercial farms have had to cull more than 1 million birds to control the outbreak, an economic blow to farmers, workers and their customers.
Merced County in central California has also been hit hard, with outbreaks at several large commercial egg production farms in recent weeks.
Experts say bird flu is spread by ducks, geese and other migratory birds. Waterfowl can carry the virus without becoming ill and it is easily spread through droppings and nasal discharge to poultry and turkey farms and backyard flocks.
California poultry farms implement strict biosecurity measures to prevent the spread of disease. State veterinarian Annette Jones urged farmers to keep their flocks indoors until June, when organic chickens must have outdoor access.
“The migrations are going on for another two months. So, we need to be as vigilant as possible to protect our birds,” said Bill Mattos, president of the California Poultry Association.
The loss of local chickens pushed up egg prices in the San Francisco Bay Area over the holidays, before supermarkets and restaurants sought suppliers from outside the region.
Although bird flu has been around for decades, the current outbreak of the virus, which began in early 2022, has prompted officials to cull nearly 82 million birds, mostly egg-laying chickens, in 47 US states, according to the US Department of Agriculture. Whenever disease is detected, the entire herd is slaughtered to help control the spread of the virus.
In January 2023, the price of a dozen eggs doubled to $4.82. As egg producers built up their flocks, egg prices returned to their normal range and outbreaks were contained. Turkey and chicken prices also rose somewhat, partly because of the virus.
“I think this is an existential issue for the commercial poultry industry. The virus is present on every continent except Australia at this time,” said Maurice Pitesky, a poultry expert at the University of California, Davis.
Climate change increases the risk of outbreaks as changing weather patterns disrupt the migratory patterns of wild birds, Bidesky said. For example, last year's exceptional rainfall created new waterfowl habitat across California, including in areas near poultry farms.
In California, the outbreak has affected more than 7 million chickens in about 40 commercial flocks and 24 backyard flocks, with most of the outbreaks occurring in the North Coast and Central Valley over the past two months, according to the USDA.
Industry officials worry that the proliferation of backyard chickens could spread infections and bird flu to commercial farms.
“We have wild birds that are full of the virus. If you expose your birds to these wild birds, they will become infected and sick,” said UC Davis researcher Rodrigo Gallardo, who studies avian influenza.
Collardo advises owners of backyard chickens to wear clean clothes and shoes to protect their flocks from infection. If an unusual number of chickens die, they should be tested for bird flu.
Ettamarie Peterson, a retired teacher in Petaluma, has a flock of about 50 hens that produce eggs that she sells for 50 cents each.
“I'm very concerned that this avian flu is spread by wild birds, and I can't stop wild birds from coming in and leaving the disease behind,” Peterson said. “If your herd has any cases, you must destroy the entire herd.”
Sunrise Farms, started by Weber's great-grandfathers more than a century ago, suffered despite strict biosecurity measures to protect the herd.
“The virus got really bad for the birds, and you got in quickly and the birds died,” Weber said. “Heartbreak doesn't describe how you feel when you walk in and perfectly healthy young birds are now set.”
After euthanizing more than half a million chickens at Sunrise Farms, Weber and his staff spent the Christmas holiday disposing of the carcasses. Since then, they have been cleaning and disinfecting the chicken houses.
Weber hopes the farm will get approval from federal regulators to bring the chicks back to the farm this spring. Then it takes another five months for the hens to mature enough to lay eggs.
He feels fortunate that two of his company's co-owned farms have not been infected and are still producing eggs for his customers. But recovering from the outbreak will not be easy.
“We have a long way to go,” Weber said. “We're going to make it another run and try to keep this family of employees together because they've worked so hard to make it into the company.”