The Cost of Eggs? How Bird Flu is Impacting Greater Yellowstone

As much of the nation sees increasing poultry and egg prices, some are pointing to inflation and supply issues. But agricultural experts lay blame on another culprit for the sky-high costs: the recent outbreak of the highly pathogenic avian influenza A (H5N1) infection, commonly known as bird flu. 

Egg prices are at a record high and expected to continue increasing, according to new figures published by the U.S. Department of Agriculture. This outlook predicts the price of eggs will increase 41 percent this year amid a widespread bird flu outbreak — more than double the 20 percent jump in prices the agency predicted a month ago. But the economic cost merely scrapes the surface.

Even as avian flu ravages the egg market, genetic mutations observed in the virus are prompting scientists to worry that the virus could infect humans at a larger scale. This comes as the first person in the U.S. died of bird flu in January.

More than 166 million wild, commercial and backyard birds have been infected nationally since the outbreak began in 2022, according to the Centers for Disease Control and Prevention. Figures published by the USDA on March 11 show that in the last 30 days alone, more than 8.4 million birds have been affected by the virus.

Nearly 164,000 birds have been infected in Montana so far, but viral infections extend beyond avian species. To date, 23 cases of H5N1 have been recorded in mammals across 17 counties in Montana, 11 in Idaho, and eight in Wyoming. 

H5N1 is one of several types of influenza A virus that primarily infects birds, colloquially known as avian influenza or bird flu. There are two types of H5N1: one is low pathogenic (LPAI) and another is highly pathogenic (HPAI). Pathogenicity refers to “the ability of the virus to produce disease,” according to the USDA.

Since the recent HPAI outbreak began in February 2022, the USDA’s Animal and Plant Health Inspection Service has tracked cases of domestic and wild mammals infected with the virus. This database includes at least 521 virus cases of infections in mammals, including pet cats, raccoons, rodents, skunks and even bottlenose dolphins. 

In Montana, the USDA database includes an infected grizzly bear in Teton County and a red fox in Madison County in December 2022. Four domestic cats were infected in Missoula, Yellowstone and Flathead counties between November 2023 and February 2025. Infected mammals in Greater Yellowstone include red foxes, striped skunks, and mountain lions.

The extent to which viral transmission occurs in species other than birds isn’t yet fully understood. Before recent HPAI strains were detected, researchers note that avian flu infections were uncommon in non-bird species.  

But since last year, health officials have recorded 70 cases of bird flu in humans, one of which resulted in the death of an elderly patient in Louisiana on January 6. While the agency still considers the virus a “low” public health risk, it remains contagious and can spread to livestock, which can, in turn, infect humans.

“There is potential for wild birds to transmit [H5N1] directly to commercial poultry and dairy cows where infected birds interface with agricultural sectors,” said Diann Prosser, a research wildlife biologist with the U.S. Geological Survey’s Eastern Ecological Science Center.

Last month, officials observed a new strain of the virus circulating in Nevada and Arizona dairy cows, the only states where the new genotype has been reported. While authorities say infection risk to the general public is low, the Central Nevada Health District warns that “people who work with birds, poultry or cows, or have recreational exposure to them, are at higher risk.” 

Montana State Veterinarian Tahnee Szymanski says the flu strains affect different animals in different ways. “Many influenza A viruses tend to be relatively species-specific,” she said. “For example, there are equine, canine, porcine, and poultry influenza A viruses.” But in some cases, she adds, influenza A viruses like bird flu can transmit between species, as has been observed between cattle and humans this year.

Monitoring these jumps between species can be challenging. State data may not always align with federal databases, particularly as funding cuts and communication blackouts persist between health agencies like the CDC, the National Institutes of Health, and the Food and Drug Administration.

In a February 28 update, for example, Gallatin County initially reported "no confirmed cases in mammals” (that version is archived here), but did not specify at the time period that the data encompassed. The USDA database, however, included cases of influenza in a skunk in 2022 and a striped skunk the following year. The county updated their figures after a conversation with Mountain Journal.

Montana Fish, Wildlife and Parks veterinarian Jennifer Ramsey says it’s difficult to fully estimate the true level of mammal exposure and infection. 

“We don’t have a way to know the true number of wild mammals affected,” said Ramsey, but added that ranchers may not need to panic quite yet. “While scientists continue to follow and study the epidemiology of this virus, to date it does not appear that wild mammals are playing a significant role in transmission to livestock.” 

Holly Matkin, communications officer for the Montana Department of Health and Human Services, says that while no human cases of H5N1 have been identified in Montana residents, the disease could potentially adapt to spread between people through viral mutations. 

“There is no current evidence that the type of HPAI currently circulating in animals in the U.S. is spreading from human to human,” Matkin said. “HPAI is shed heavily in the secretions of infected birds, which includes saliva and feces. Activity in environments such as lakes heavily coated in waterfowl feces may pose an elevated risk of HPAI infection. HPAI is also shed heavily in the milk of infected dairy cattle.”

Though avian flu is currently considered a low risk, the CDC warns that the virus can potentially cause “severe disease in infected humans.” The agency recommends people protect themselves by limiting exposure to potentially infected animals. 

In people, symptoms of avian influenza resemble the human flu and include fever, cough, sore throat, muscle aches, headaches, and fatigue. Another commonly reported symptom specific to HPAI is conjunctivitis in the eyes.

Health professionals say there is no risk of contracting bird flu from eating commercial eggs, poultry or pasteurized dairy products. However, there is a likelihood the virus could survive in unpasteurized products like milk. “Safe cooking and handling of eggs, poultry and meat is always recommended,” Matkin said. 

Infected wild birds are often found dead but may display neurological symptoms before death, such as lethargy, an inability to fly, incoordination, weakness and convulsions, according to Ramsey. Similarly, infected wild mammals are often found dead but may display neurological symptoms and abnormal behavior, incoordination, lethargy and tremors. 

“When sick wild mammals are detected, especially those demonstrating neurologic symptoms, they can be reported to FWP so that we can assess whether the animal should be prioritized for follow-up or potential testing,” Ramsey said.

Dairy cattle may experience changes in milk production or appearance, respiratory disease, abnormal feces or fever. 

Ramsey says backyard birdkeepers should look for abnormal behavioral changes like decreased appetite, huddling and closed eyes. Birds may also lay reduced or misshapen eggs and experience watery diarrhea, excessive thirst, or swollen wattles and combs.

Experts are encouraging commercial and hobby farmers to follow USDA guidance on biosecurity to protect themselves and their animals.

“If someone has suspicion that an animal is infected with avian influenza, they should work with their local veterinarian or report the sick animal to our office or FWP if it is a wild animal,” Szymanski said. 

Montana officials warn that as HPAI continues to be detected across American skies, protective measures should be implemented until at least July 31.