Your questions about bird flu, answered

Sky-high egg prices have drawn renewed attention to the bird flu outbreak, which has caused more than 166 million wild and domestic birds in the U.S. to die since it began in 2022.

While the health risk to most people remains low, the outbreak has continued to surprise researchers and the federal government has been unable to wrangle it under control.

“It seems like another battle keeps popping up day after day,” said Andrew Bowman, an influenza expert at Ohio State University’s College of Veterinary Medicine. “I really hate saying ‘unprecedented,’ but it sure feels different than anything before.”

NBC News asked its readers on social media what they wanted to know about the outbreak, mitigation measures and eggs. Here are the answers to your (lightly edited) questions.

Is it safe to buy and eat chicken? What about eggs? And milk?

Yes, it’s safe to buy and eat poultry products, which are tightly regulated and frequently tested. Moreover, the virus is eliminated through cooking.

“Between testing and safe food handling, any poultry being consumed from a grocery store would be safe in my mind,” Bowman said, adding that flu viruses are “very easy to inactivate via heat.”

The Food and Drug Administration continues to recommend cooking eggs until both the yolk and white harden.

Eggs from backyard flocks that have direct contact with migrating waterfowl might be more concerning, but avian influenza generally hampers egg production and causes most birds to die.

“Birds that have avian influenza die and they’re sick and they don’t lay eggs,” said Amber Itle, the state veterinarian of Washington state.

In milk, meanwhile, pasteurization inactivates the virus, making commercially produced milk safe for consumption. However, raw milk is extremely risky because the virus replicates in cows’ mammary glands.

“That’s where the virus is in the dairy cows,” said Dr. Peter Chin-Hong, a professor of medicine at the University of California San Francisco who studies infectious diseases.

How does bird flu spread on farms?

Avian influenza, or H5N1, is an extremely contagious and deadly respiratory virus for birds. Once infected, the animals rapidly replicate the virus and spread it through airborne particles, feces, droplets of saliva and nasal excretions.

Some recent, early studies suggest that the virus can even travel from farm to farm in dropping particles carried by the wind.

On dairy farms, infected cows shed the virus through their mammary glands, so they are most likely infected through milk and during milking.

Studies suggest that farm cats have gotten the virus from drinking raw milk.

Is the only way to stop bird flu to kill off all diseased birds?

When a bird flu outbreak is identified, federal policy requires that the virus be stamped out, meaning all the birds must be culled, or “depopulated.”

There are few other options once the virus begins to infect a farm or backyard coop, given that any surviving birds could spread the virus further. Most would die either way.

“I think it’s safe to say, we’d expect over 80% mortality,” Bowman said. “If you let it continue to smolder, will you have some birds that survive? Yes, you will. But at what cost? Because you have to view each one as replicating and making more virus.”

The U.S. is also investing in enhanced biosecurity measures to stop bird flu from reaching farms. Strict programs require workers to shower in and out at work sites, regularly disinfect barns, prevent wildlife from getting in and wash vehicles, among other measures.

Bowman said those strategies help, but it’s still tough.

“It’s kind of easy to have a lapse in biosecurity someplace. Think about telling your kids to pick up their room every day. Do we ever get a day where someone doesn’t do it — well, that’s the day the virus gets in,” Bowman said.

Unlike birds, cows can recover after a bird flu infection, so they do not have to be culled.

How many egg-laying hens have been culled versus chickens raised for meat?

Egg farms have taken the harder hit.

In January, about 23 million birds were culled on American farms, according to the U.S. Department of Agriculture. Of those, about 18.8 million were “layers” bred to produce eggs while just 2.2 million were “broilers” raised for meat.

“We’re not seeing drastic reductions in the broiler flock compared to the laying flock,” said John Cranfield, a professor and agricultural economist at the University of Guelph in Ontario, Canada.

Layers and broilers are different birds with different genetics. The lengths of their lives also differ, making egg production more exposed to the virus.

“It takes about a month and a half, maybe seven weeks to get a broiler chicken to its market weight,” said John Cranfield, a professor and agricultural economist at the University of Guelph in Ontario. “Whereas an egg-laying hen is going to be about five months to get to the point of laying eggs and then it’s probably going to be laying eggs for a year.”

Since January 2020, the price of a carton of eggs has risen from about $1.46 on average to $4.95, according to Federal Reserve data. Meanwhile, a pound of chicken breast has risen from $3.06 to $3.97.

Eggs are also more difficult to replace in people’s diets.

“Even with big changes in prices, there’s very little change in demand,” Cranfield said.

What happens to the carcasses?

How affected birds are killed depends on how a farm is set up, the species and the number of birds. To mass-cull birds, options include spraying foam throughout a barn to suffocate the birds quickly, and gassing them by rapidly increasing the C02 concentration or by shutting down ventilation (the most controversial method).

Itle said Washington state views the CO2 method as most humane. Overall, she said, culling birds takes a toll.

“It’s the worst part of my job and it’s been really, really hard on myself, on responders who are on these cases and for farm workers, because we’re all in this business to protect animal health,” Itle said.

At smaller operations, birds’ carcasses are often incinerated. When large commercial flocks are infected, carcasses are composted in a specialized process that involves heat, added nitrogen, water and microorganisms.

Itle said compost piles can stretch for miles at a big farm. Workers will turn the piles and check their temperature and ensure it reaches 131 degrees Fahrenheit for three days in a row to inactivate the virus.

“Composting is lovely. It’s such a good, sustainable way of dealing with this virus,” Itle said. “At the end of the day, you get this great nutrient rich product where the viruses have all been inactivated.”

Are ducks, crows, pigeons and other birds dying, too?

Avian influenza is circulating widely among wild birds. The USDA has confirmed infections in more than 12,000 wild birds across more than 170 species.

Bird flu outbreaks on farms have been tied to seasonal migrations of wild birds, which can contaminate equipment and feed, and infect poultry through droppings or direct interactions.

Can bird flu spread from animals to crops?

Experts are not very concerned about crop contamination.

“There’s a good reason to wash vegetables — shigella, E.coli, listeria,” Chin-Hong said. “Your risk of getting those other foodborne disease are higher than getting bird flu.”

Can bird flu spread among people?

Scientists don’t think there have been cases of human-to-human transmission yet, but research suggests that it could be possible if the virus mutates.

Of the 70 human cases confirmed in the U.S. so far, most have been in farmworkers.

But the more times the virus jumps from animals to people, the greater the risk that it will undergo random genetic changes that would enable it to spread person to person.

“The fewer transmission events you have, you lower the risk of random mutations to figure out the combination to get into our bodies,” Chin-Hong said.

Will bird flu become the next human pandemic?

Scientists have worried for decades about this version of bird flu because human immune systems have not dealt with it before. The sheer amount of virus in wild birds and farm animals does increase the risk of it spreading to people.

“I can’t promise this particular bird flu will be the next big one, but there have been four influenza pandemics since the beginning of the 20th century and they all have had their origins in avian flu,” Chin-Hong said.

Are there bird flu vaccines for people?

The federal government has two bird flu vaccines stockpiled, but they would need FDA authorization.

Scientists are also developing new vaccines using mRNA technology, which was first used against Covid. But Bloomberg reported that the Trump administration was weighing whether to pull funding for an mRNA bird flu vaccine being developed by Moderna.

Is there a vaccine strategy for chickens?

Chickens can be vaccinated against bird flu, and countries like France are already doing so. But the USDA has not approved such a vaccine.

So far, the U.S. has been resistant to a chicken vaccination strategy because exporters of poultry participate in a program that requires testing for avian influenza antibodies in flocks. The antibodies are evidence of an immune response to a viral infection, but vaccines would lead chickens to produce the same antibodies, which would confuse the results.

“We do have vaccines that have been proven efficacious,” Bowman said, but added that “to put a vaccine on the market, we’d also have to change the entire testing assurance strategy and we’d have to negotiate that with all our trade partners.”

Any vaccination strategy would also have to account for the fact that vaccines wouldn’t eliminate infections or illnesses entirely, and that wild birds that spread the virus wouldn’t receive vaccines.

Nonetheless, the Trump administration is putting $100 million toward research on vaccines and therapeutics for poultry.

In a news conference last month, Agriculture Secretary Brooke Rollins described vaccination as a potential solution, but said more testing is needed.

“We’re just not ready. We don’t have enough information,” Rollins said. “Before we start sticking our chickens, we need to ensure — before putting that in the food supply — we know exactly what we’re doing.”

Researchers are in the process of testing vaccines for cows, too.

Has President Trump announced any plans to support farmers? Can they expect aid?

The USDA already provides payments to poultry farmers who have suffered bird flu outbreaks, in part to incentivize early reporting.

“When birds are euthanized, we pay them for every live bird that’s left that we have to depopulate,” Itle said.

Through November 2024, the government had paid about $1.25 billion in indemnity and compensation, according to the USDA. Indemnity payments vary, with different prices for “broiler” versus “layer” chickens.

Some additional funds are available for the costs of culling animals, disposing of their bodies and disinfecting farms afterward.

The USDA announced an additional $1 billion plan to address bird flu last month, of which $400 million is meant to help speed the process for farmers to clean and repopulate their farms, which usually takes about six months.

How long until egg prices fall?

No one knows, since it depends on how quickly officials can get the outbreak under control. And even once that happens, “it’s probably a couple of months at a minimum before they start to see some relief,” Cranfield said.

In the meantime, the USDA’s efforts to help egg producers get back on their feet more quickly after a flock is infected may help a bit.

Bowman said that if he was forced to shake his Magic 8 Ball, he’d say the outbreak may start to slow over the summer.

“A lot of this is tied to the spillover — the virus moving with migratory waterfowl,” he said, explaining that migratory birds hatch in the spring, then travel and mix together during the fall. “They amplify virus, new virus strains emerge and spill over, we have that cycle for a while.”

Will tariffs affect egg prices?

It’s not clear yet, though it’s possible.

Any added costs for farmers — due to more expensive fertilizer, fuel or equipment — would factor into the price of eggs. The U.S. imports Canadian potash for fertilizer that’s used to grow grains in chicken feed, Cranfield said. However, the Trump administration has announced some exceptions to the sweeping tariffs it issued, including potash, through April 2.

The USDA last month predicted egg prices will be more than 40% higher in 2025 than in 2024.

Why haven’t milk prices gone up the same way eggs have?

Cows can recover after a bird flu infection, and the outbreak in dairy cows has not been as overwhelming as in poultry.

“We just haven’t seen the same scale of outbreak as we have with birds,” Cranfield said, adding that federal milk pricing policies also provide some stabilization.

If I have birds of my own, how can I protect them?

Pay attention to your animals’ health, limit their exposure to wild birds, keep their enclosures clean and report sick animals.

Are my pets at risk of bird flu?

Cats may be.

The California Department of Public Health documented cases in which cats were sickened after drinking raw milk, and other cats have been sickened after eating rawcat food. The Centers for Disease Control and Prevention also documented a case in which people passed the virus to cats.

“Don’t feed them raw milk; don’t feed them raw meat,” Chin-Hong said, adding that outdoor cats will be at greater risk. “Try to not have the cat drink water from a bird feeder.”

Dogs don’t seem to be particularly susceptible, Itle said.

Is it risky if me or my child comes in contact with wild birds or bird poop?

The risk of contracting the virus from the environment remains low, as long as you’re not at a farm. The CDC has only reported a few cases in which there was no known source of exposure.

“Because the virus isn’t adapted yet to humans, it’s like forcing an ill-fitting key into a lock,” said Chin-Hong. “The people who have gotten it are in constant contact with high viral loads. That’s why dairy workers are at risk. They’re getting constantly bombarded.

To be safe, though, don’t handle dead birds and make children wash their hands — best practices regardless of bird flu.

This article was originally published on NBCNews.com