Nearly 1 million chickens were killed at an Illinois farm after a bird flu outbreak became the nation’s largest active outbreak this week.

The outbreak affected 934,600 birds at a commercial table egg layer facility in Clinton County, Illinois, the United States Department of Agriculture confirmed. It reportedly occurred at Rose Acre Farms, located outside Germantown, village officials told KSDK.

Rose Acre Farms is the second-largest egg producer in the U.S., according to the company’s website. With no treatment available for highly pathogenic avian influenza, better known as bird flu, authorities must kill infected and exposed birds to contain the virus.

Losing nearly a million hens could disrupt egg production and put further pressure on prices as supplies tighten.

The scale of the Illinois outbreak far exceeds other active cases nationwide. Minnesota had the next-highest number of birds affected, with 168,880 statewide, according to the USDA.

The outbreak is part of a nationwide bird flu epidemic first detected in the U.S. in February 2022. Since then, more than 210 million birds have died or been killed as a result of the outbreak, according to the report.

Bird flu detections typically increase during the fall and spring, when migrating wild birds can spread the virus to domestic poultry. The virus can spread through contact with infected birds, contaminated surfaces and materials, making farms vulnerable when the disease reaches their flocks.

Replacing nearly a million hens takes time, meaning fewer eggs could reach grocery stores and prices could rise. That’s what happened in 2024, when bird flu killed tens of millions of egg-laying hens, shrinking supplies and sending prices soaring.

By January that year, a dozen cage-free eggs averaged $5.26 in advertised retail prices, according to the USDA. As of last month, the national averages were sitting around $3.80 to $3.88, according to the agency.

The Trump administration even sued California and Michigan over cage-free egg laws, arguing the state requirements drive up prices and that egg production should be governed by federal standards. The lawsuits were dismissed, with judges finding the administration had not established it had legal grounds to bring the challenges.

The USDA’s Animal and Plant Health Inspection Service said it continues to work with state animal health officials to monitor commercial poultry operations, backyard flocks and wild birds for signs of infection.

“We also continue to encourage all bird owners to practice strong biosecurity—that means reducing opportunities for wildlife to spread the virus to their birds and preventing the spread of the virus from one premises to another,” the agency said on its website.

The Independent has contacted the USDA and Rose Acre Farms for comment.