Bird Flu Update 2025 –Backyard Flock Keepers’ FAQ’s
Sanshui, a medium sized city in China's southern coastal Guangdong province, is home to the region's Budweiser brewery and its Red Bull factory. More significantly, it is the center of an important agricultural region. In the early spring of 1996, a farmer near Sanshui noticed one of his geese behaving oddly. It appeared sluggish, uncoordinated, and sick. The goose deteriorated quickly and died. Within a matter of hours, other geese in the flock showed similar symptoms. Each one of them also died. Within days, geese, ducks and chickens throughout Guangdong were dying with the same alarming symptoms. It was the beginning of the H5N1 avian influenza outbreak that now covers the planet.
The Guangdong virus spread, mutated and evolved, giving rise to new subtypes. Soon the first human cases appeared—people who caught the infection from their flocks. The virus moved around China with the sale of domestic poultry. Then migratory birds became infected and spread an assortment of H5N1 subtypes around world.
H5N1 first came to U.S. poultry flocks in 2014, causing a severe outbreak. The U.S. ramped up its strict avian flu response—strict biosecurity measures and the “depopulation” of infected flocks. The outbreak was contained in the U.S. and H5N1 disappeared. For a while.
The virus was still alive and mutating into new forms in other parts of the world. In 2020, in the midst of Covid, a tenacious, infectious new H5N1 clade emerged in Asia - 2.3.4.4b. This new H5N1 mutation spread through poultry flocks. Then it found its way to North America.
In 2022, as 2.3.4.4b was ramping up in the U.S., at the request of some folks at the CDC, I wrote a three-part series of articles on bird flu. The information I wrote in those three-year-old articles is still relevant because that bird flu epidemic is still with us! And that’s surprising a lot of people. There have been bird flu outbreaks in U.S. poultry flocks in the past. Animal health officials developed strategies to deal with those outbreaks and they have worked well. Those control measures arrested and eliminated the bird flu outbreaks of 1983, 2004 and 2014.
But this time, the virus is not slowing down. To date (June 2025), in the U.S., over 174 million commercial poultry birds have been culled. Egg prices have increased astronomically. It’s in cats now, and over 80 other mammal species. It’s in dairy herds in many states; thus, it’s in dairy products. 70 people have become infected, and in January of this year, the first human died.
There’s growing concern and lots of questions from backyard poultry keepers. “What, exactly, is bird flu? Are my chickens in danger? How can I protect them? Am I in danger? If I am, how should I protect myself? Why do we keep having new epidemics? Is there something wrong with the way they’re trying to stop it? There’s talk of a new approach to controlling it—how’s that going?
I’ve written this article as an update to my original bird flu series to provide some answers those frequently asked questions.
What is Bird Flu?
You’ve probably had the flu before—fever, aches, and too much daytime TV while you’re stuck on the couch. The virus now killing chickens is a close cousin to the one that made you sick. In fact, all flu viruses—whether they infect humans, pigs, horses, dogs, cats, bats, foxes, skunks, or you name the animal—belong to the same big family: Orthomyxoviridae.
This shared relationship is key to understanding flu. Bird flu, human flu, and all flu—it’s all related. Flu is flu is flu. And sometimes, a flu virus mutates and jumps to a new host species. When that happens, the consequences can be devastating. The new host has no immunity, so the virus spreads rapidly. That’s how pandemics start. In 1918, for example, a bird flu strain jumped to humans, triggering the “Spanish Flu” pandemic, which infected a third of the world’s population and killed an estimated 50 million people.
Edoardo Perroncito (public domain)
Bird flu has likely existed for centuries, but we only began to understand it after microbiology emerged as a science. In 1878, Italian veterinarian Edoardo Perroncito described a mysterious disease wiping out poultry flocks. He called it “fowl plague.”
By 1880, microbiologists Sebastiano Rivolta and Pietro Delprato realized this “plague” was actually two different diseases. One was caused by a bacterium we now know as Pasteurella multocida, responsible for fowl cholera. The other one was so small that it passed right through filters that captured bacteria.
Back then, viruses were unknown—but the concept of "contagium vivum fluidum" e.g. “living fluid” was starting to emerge. Scientists discovered that they could spread certain diseases by passing from animal to animal a liquid suspension of tiny unfilterable particles too small to be seen under a microscope. These minute particles would not grow in the laboratory but needed a living host in order to live and reproduce. And thus, viruses were discovered. By 1901, viruses were an established disease agent and fowl plague was recognized as a viral disease.
Once fowl plague had a name and a description, reports of outbreaks came in from across Europe. In 1924–1925, the first U.S. cases were found in New York City’s live bird markets.
By the 1950s, mass bird deaths from fowl plague were being reported globally. In 1957, another human flu pandemic killed over a million people, raising suspicions of a bird-human virus link. When another human pandemic hit in 1968, better lab tools confirmed the connection. In 1981, scientists gathered for the First International Symposium on Avian Influenza and decided that it was time to call fowl plague what it really was: Avian Influenza. Bird Flu.
Today, bird flu viruses are classified as either low-pathogenic (LPAI) or highly pathogenic (HPAI). LPAI strains circulate constantly in wild birds. In backyard flocks, they might go unnoticed or cause only mild symptoms like ruffled feathers or fewer eggs. HPAI is far more dangerous. It spreads fast, causes severe illness, and can wipe out an entire flock. Alarmingly, LPAI can mutate into HPAI.
The current dominant strain—H5N1 clade 2.3.4.4b—was first detected in wild birds in the U.S. in the Carolinas in December 2021, and then in Indiana poultry in February 2022. Since then, it has spread across the U.S. It’s one seriously nasty virus.
How Do We Fight Bird Flu?
When bird flu strikes poultry flocks, U.S. animal health experts follow a tried-and-true strategy developed during past outbreaks. This approach has consistently helped contain the disease. There are six main strategies:
Biosecurity: Wild birds are the main carriers of avian flu. To reduce the risk of the virus spreading to poultry, the USDA inspects farms to find and fix potential points of contact with wild birds. They also perform biosecurity audits and often help pay for needed improvements.
Monitoring: To catch outbreaks early, the USDA tests both poultry and wild birds. In 2022, they ran more than 1.8 million tests on poultry and collected nearly 21,000 samples from wild birds.
Quarantine: If bird flu is detected, a control zone is established around the infected site. Movement of poultry and poultry equipment in and out of the area is strictly limited.
Depopulation: All poultry within the control zone are euthanized.
Disinfection: After depopulation, each facility is thoroughly disinfected.
Testing: After disinfection, each facility is rigorously scanned for the presence of the bird flu virus.
This protocol has been the backbone of the U.S. response to avian flu in poultry for decades.
Why Isn’t the Established Strategy Working This Time?
When clade 2.3.4.4b emerged in early 2022, the U.S. already had strong prevention and control measures in place. As always, officials responded swiftly—using surveillance, biosecurity, quarantine, culling, and disinfection. But despite these efforts, the virus kept spreading. Why?
There’s no simple answer. Experts have some ideas, but much of it is still speculation. Here's what might be going wrong:
New Hosts and New Routes of Transmission
Clade 2.3.4.4b is proving unusually adaptable. In the past, avian flu mostly spread through certain migratory waterfowl. Now, this strain is infecting a much wider range of birds, including cormorants, pelicans, vultures, hawks, and falcons. This expansion makes the virus harder to monitor and control.
As University of New South Wales epidemiologist Raina MacIntyre puts it: “We’ve got to think beyond ducks, geese, and swans. They’re still important, but we have to start looking closely at these other species and other routes and think about what new risks that brings.” Many of these new bird hosts show few or no symptoms, which means the virus can spread silently.
The virus isn’t just spreading through birds. It has also jumped to more than 80 species of mammals. The ABC’s of infected mammals include alpacas, bears, and cats, then goes on to include dolphins, elephant seals, fishers, goats, and a whole host of others. You can see the full list here. There is strong evidence of mammal-to-mammal transmission among wild sea mammals such as sea lions, marine otters, porpoises and dolphins. And there is one proven case of direct mammal to mammal spread at a Spanish mink farm where over 50,000 mink were eventually euthanized. Direct mammal-to-mammal spread is alarming because such transmission could bring the virus a step closer to human-to-human transmission and an ensuing pandemic.
Its adaption to new mammal hosts also allows new transmission pathways. For instance, its infection of dairy cows has allowed transmission through milk.
Surveillance Weaknesses
While the USDA offers biosecurity and testing programs for poultry and livestock farms, participation is voluntary. Many farms opt out, leaving large parts of the country essentially unmonitored.
As the virus spreads into cattle, current rules haven’t kept up. Milk testing only started recently. With poor data and gaps in testing, it is likely that officials are underestimating the true scale of the outbreak.
Monitoring wild birds presents an even bigger challenge. Monitoring the virus in one or two wild bird species is challenging. Monitoring it in multiple species is impractical to impossible.
A Slow Response to A Rapidly Changing Virus
Flu viruses are successful because they can evolve and adapt quickly. Government responses typically evolve and adapt glacially. Updating official strategies can take months of bureaucratic review and political debate. By the time a new policy is approved, the virus may have already evolved again. In short: the virus is nimble. The response is not.
Factory Farms
Modern industrial farms cram thousands of animals into confined, often unsanitary spaces. This creates ideal conditions for viruses to mutate and spread.
The Humane League (THL) argued in June 2024 that many livestock diseases could be reduced by moving away from intensive confinement. THL president, veterinarian Vicky Bond, put it bluntly: We’ve created a system “in which thousands of animals are packed into dense, unclean living quarters—creating conditions ripe for disease…The threat remains high unless we collectively change our relationship with nonhuman animals."
Science writer David Quammen echoed the THL statement in this 2024 New York Times essay, calling factory farms “petri dishes for the evolution of novel pathogens.” With so many animals raised in such close quarters, he argued, it's no wonder new viruses are emerging and spreading to humans.
Bottom Line
The old playbook isn’t enough anymore. The virus has changed. The environment has changed. And without stronger surveillance, faster responses, and rethinking how we raise animals, avian flu may continue to outpace our efforts to stop it.
What Is the New “Five Pronged” Strategy to Fight Bird Flu?
In response to the ongoing bird flu crisis, the new administration announced a fresh strategy in early 2025. On February 26, the U.S. Department of Agriculture (USDA) released a statement titled “USDA Invests Up to $1 Billion to Combat Avian Flu and Reduce Egg Prices.” In the release, USDA Secretary Brooke Rollins introduced a new five-pronged approach to fight the virus and stabilize the egg market. The five prongs:
1. Strengthen Biosecurity
Expand the Wildlife Biosecurity Assessments Program to poultry farms nationwide since wild birds are the main avian flu vector to domestic poultry. So far, only one of the approximately 150 participating facilities has had an outbreak.
Offer free biosecurity audits to both infected farms and nearby farms. Farms must correct problems to remain eligible for future USDA payouts.
Cover up to 75% of fix-it costs, with a total of $500 million available to help farms address major biosecurity risks.
Send 20 trained epidemiologists to help farms improve defenses against wild bird transmission and bird-to-bird spread.
2. Increase Support for Farmers
Continue compensating farms that must cull flocks due to avian flu infection.
Provide up to $400 million in recovery aid this year to help farms rebuild.
3. Cut Red Tape
Explore ways to scale down depopulation during outbreaks where possible.
Inform consumers and Congress about how regulations affect egg prices, especially in high-cost states like California.
4. Advance Vaccines and Other New Tools
Spend up to $100 million on vaccine research, treatments, and biosurveillance.
Work with global trade partners to minimize export disruptions caused by vaccination, since some countries won’t accept eggs from vaccinated hens.
5. Explore Temporary Trade Options and Global Best Practices
Consider short-term increases in egg imports and reductions in exports to ease prices at home.
Study successful international practices to improve U.S. egg production and food safety.
Will the Five Prongs Stop Bird Flu?
When Secretary Rollins introduced the plan, she acknowledged the challenge ahead. “There’s no silver bullet,” she said, explaining the need for a five-pronged approach. But now, months later, many experts are questioning whether this plan is actually better—or just more of the same, with some serious blind spots.
Where Are the Details?
USDA Secretary Brooke Rollins (public domain)
The February rollout offered only a broad outline. Now, in late June, key details are still missing. How will new testing, audits, and inspections be implemented? What are the timelines? The USDA hasn’t said.
And there’s a bigger problem: staffing. The USDA has lost hundreds of inspectors due to federal cost-cutting, and the Department of Health and Human Services has shed 10,000 workers, including personnel from the FDA’s Veterinary Laboratory Investigation and Response Network—a vital part of the H5N1 testing system. The plan assumes more work with fewer people. That’s a recipe for failure.
Poultry Vaccinations – Not So Easy:
One prong of the new plan suggests avian flu vaccinations for flocks. This strategy is already in place in other countries, and vaccines already exist and are ready to go. The USDA issued a conditional license for avian influenza vaccine to Zoetis in February. Things are definitely moving at warp speed for a chicken vaccine! And vaccinated birds don’t get flu. So, roll up your sleeve and stick out your wing! Problem solved, right?
Well, unfortunately, it’s a bit more complicated than that.
These are “leaky” vaccines, meaning they protect chickens from getting sick, but not from carrying or spreading the virus. Even worse, vaccinated birds test positive in standard flu screenings, making it nearly impossible to detect outbreaks within flocks. Chickens with undetected virus would likely wind up in our food supply. While cooking kills the virus, what consumer will want to buy chickens that may be infected with bird flu? Certainly not the consumers in many of the countries we trade with—which is why many countries have bans against importing meat from countries that vaccinate poultry.
Vaccination could also backfire by creating silent reservoirs of the virus, giving it more opportunities to mutate and possibly become more dangerous.
There’s also a divide within the poultry industry:
Egg producers support vaccination because it’s cheaper than culling flocks.
Broiler producers oppose it because their birds live shorter lives and face less risk—and because vaccines could jeopardize exports, a big part of their business.
And even if the industry agreed on vaccines, logistics are a nightmare. Some farms house millions of birds. How do you vaccinate every one of them by hand? Labor shortages, worsened by immigration enforcement, make this even harder. Farmers want vaccines that could go into poultry water or feed, but they don’t exist yet, and manufacturers won’t develop them without guaranteed demand.
It's Not Just Chickens!
Though billed as a broad strategy, the plan is almost entirely focused on laying hens. What about turkeys and other poultry? What about dairy cattle and other mammals? What about wild birds? For example:
Dairy cows in 17 states are infected. While not often fatal, the virus lowers milk output and forces destruction of infected milk.
Pigs are particularly dangerous because they can host both human and bird flu viruses—allowing the viruses to swap genetic material and possibly create new, human-infecting strains.
Senator Amy Klobuchar, the ranking member of the Senate Committee on Agriculture and three other senators wrote a letter to Agriculture Secretary Rollins in April urging that the new initiative also include measures for turkeys and dairy herds. So far, there’s been no public response.
At the same time, funding for avian flu programs abroad and for wild bird surveillance in key migratory zones is being cut. These programs are essential for early warnings and global containment.
Ignoring a Root Cause: Factory Farms
One of the main reasons bird flu keeps spreading is the structure of modern poultry farming. Millions of animals are packed tightly together, creating ideal conditions for viruses to thrive and mutate. Yet the new USDA plan doesn’t address this at all—in fact, it may undermine efforts to fix it.
Take California’s Proposition 12, passed by voters in 2018. It bans cramped cages and requires more space per animal, even for products sold in California but produced elsewhere. The Supreme Court upheld it in 2023.
But Secretary Rollins opposes Prop 12. In her confirmation hearing, she said she’d work with Congress to overturn it. The USDA’s mention of “regulations and price hikes, especially in states like California,” is widely seen as code for rolling back Prop 12.
“Repealing state bans on cages won’t stop the spread of bird flu,” The Humane League’s Senior Policy Counsel Hannah Truxell stated in an interview with Vox. “It would, however, reverse years of critical food industry progress.” This prong is not just ineffective; it is counterproductive and dangerous.
And So….
At first glance, the USDA’s five-pronged plan looks like bold action. But on closer inspection, it’s mostly a repackaging of old programs, with limited scope, incomplete implementation plans, and little attention to the bigger picture. It focuses on laying hens while neglecting turkeys, cows, pigs, and wild birds. It promotes factory farms while threatening more humane practices like those in Prop 12. And it asks an understaffed system to do more with less.
Yes, vaccines are promising—but they’re not a magic fix. And ignoring the role of high-density, industrial animal farming is a major missed opportunity.
Will this five-pronged plan stop avian flu? Not likely—not in its current form. Five prongs don’t make a right.
How Do I Protect My Flock?
I’ve written a number of articles about various infectious diseases that affect chickens. In each of those articles I’ve included a section on protecting your flock from infectious diseases carried by other chickens. All those rules apply here, but there’s also another important consideration. You also have to be vigilant against avian flu carried by wild birds.
From Other Infected Poultry
Commercial chicken operators have way too many chickens crammed into not enough space. Because of the size and density of commercial flocks, these operators have to be vigilant to prevent disease. We backyard flock folks need to be as serious about protecting our birds from HPAI as the big commercial guys. HPAI does strike backyard flocks. Frequently. It is serious, so we need to be serious with our precautions. Here’s my list:
Don’t visit other coops.
Don’t allow any unnecessary people near your chickens or in your coop.
If you must allow a caregiver or someone else in your coop, and they’ve been in contact with another coop or flock, make sure that they’ve showered and changed clothes before visiting your coop. My chicken sitter has a dedicated pair of boots just for my coop that she keeps at my house.
Don’t attend coop tours, don't enter poultry barns at the fair, don't go to swap meets or anywhere else where there are live chickens. And since you’ll probably do some or all of those things, shower and change your clothes before you visit your coop. And be sure to have dedicated shoes or boots that are only for your coop.
If you introduce new birds to your flock, or you take a bird to a show or exhibition, quarantine that bird for at least four weeks.
The USDA has a robust on-line resource center on biosecurity called “Defend the Flock.” Take a look at that and think about how you can best implement their suggestions.
From Infected Wild Birds
Wild birds are avian influenza reservoirs. They often carry the virus without showing signs of illness, and spread it far and wide as they migrate. Your backyard poultry can catch the virus by direct contact with these infected wild birds, or more likely, by coming in contact with objects or environments contaminated by them. Imagine your ducks swimming in a pond where infected wild ducks had been swimming, splashing and pooping. Or think of wild birds stopping for a bite to eat at your outdoor chicken feeder, or at the spot in the run where you scatter scratch grain.
The main carriers of avian flu are water birds like ducks, geese and swans and shore birds like gulls and terns. Raptors such as eagles, hawks and owls can contract avian influenza by eating infected birds. And vultures and crows can become infected by eating infected dead birds.
Songbirds are at low risk of carrying the disease, but they are not entirely without risk. And since there is a chance of a random songbird asymptomatically carrying avian flu, the USDA recommends that if you have backyard poultry that you take down bird feeders or keep them far away from your flock.
Biosecurity is all about keeping your flock from coming in contact with wild birds and things that wild birds have contacted.
Make sure wild birds can’t get into your coop.
Cover and enclose outdoor feeding areas with fencing or only feed your flock indoors.
Clean up spilled feed.
Don’t allow your poultry access to ponds that are visited by wild birds.
Get rid of any large puddles that could attract migrating waterfowl.
Get rid of birdfeeders or keep them far away from your flock.
Signs of HPAI:
The first signs you may notice that indicate something’s not right with your flock is when one or more hens appear sick—they will be inactive and stand alone in a corner with their head and tail down, or they’ll never leave the roost. Egg production will be down. Their combs can turn dark, and their feathers can appear ruffled. Chickens may have their beaks open, gasping for breath. They may have extreme diarrhea. Sadly, the next sign is unmistakable. Many chickens will die suddenly. If this happens in your coop, it’s NOT a done deal that your flock has avian flu, but it's certainly a sign that something is very wrong and that you need to reach out for help.
I See Signs of HPAI. Now What?
If you are confronted with the nightmare of most or all of your chickens becoming sick or dying, call your vet immediately. If you don’t have a vet, call your state animal health official. Here is a list of the animal health official to contact in each state. Or you can call the USDA's toll-free number directly at 1-866-536-7593.
Birds from your flock will be tested. If the test is positive for HPAI, by law, your entire flock will be euthanized on site. Then, veterinary health officials will test every flock within a 6-mile radius. If any other positive flocks are discovered, each flock will be retested periodically until no more positive cases are discovered. No chickens will be euthanized in neighboring flocks that test negative. By law, you will be compensated for the loss of your birds. But not for your suffering and heartbreak.
How Do I Protect Myself?
Of the seventy confirmed or suspected human cases of bird flu since 2024 that have been reported by the CDC, over half contracted the virus by exposure to infected cows. Most of the remaining cases were on large scale poultry farms. But there have been cases of people getting sick from contact with their infected backyard flocks. The single reported avian flu death was a person over the age of 65 in Louisiana with underlying medical conditions. The Louisiana Department of Health has reported that the patient contracted bird flu after exposure to both wild birds and a backyard flock. We backyard flock folks need to be vigilant. All of us.
Poultry infected with avian flu can spread the virus via their saliva or mucous, but the most likely source is their poop. Normal, healthy chickens poop indiscriminately and everywhere. Chickens sick and dying with avian flu probably have diarrhea. So, yes. Virus-laden poop will be everywhere. Consider every bird, every object, and every surface in your coop to be infected. The virus may also be present in moisture droplets and dust in the air.
If you suspect your flock has avian flu but you have not yet had confirmation, observe your flock from only a distance. If it is absolutely necessary for you to enter your coop and have direct contact with your birds, you should wear personal protective equipment such as goggles, an N95 mask, and disposable clothing and boots. The CDC’s guidance for personal protective equipment for people working with animals is here. The seasonal flu vaccine is important for protecting you from seasonal flu, but it will not protect you from this epidemic strain of bird flu. If your flock is ultimately confirmed to be infected with HPAI, follow the guidance of the public official in charge of your incident.
If you become sick within ten days of your chickens becoming ill, you should isolate at home—away from the other people in your household. Your doctor or clinic can help you get tested by your state or local department of health and will advise you about further monitoring and isolation.
When Will It All End?
Avian flu has become embedded in wild birds—it is endemic and it persists in all seasons, year-round. The herculean effort by state and federal government agencies to manage and control it in poultry and other domestic animals is not working as well as it used to and is now in a state of flux.
Right now, the threat to people is small—people can only get it from infected chickens, cows or other domestic and wild animals. That critical mutation that would allow the virus to spread human-to-human has not occurred.
When will it end? Perhaps never. This may be the new normal. So, all of us need to do all the things that are necessary and important for us to do in this situation. Stay informed. Stay safe. Protect our flocks. Speak out against bad public policy. While bird flu may never be eradicated, proficient monitoring, our precautions to protect ourselves and our flocks, and new innovations and research efforts can control it and curtail its effect.
In this brave new normal, all of us must do what we can to live our best lives. And we must do what we can do so our backyard chickens can live their best lives, too.
