A research veterinarian gives practical advice to homeowners for how to protect themselves and their flocks.

By Meg Wilcox

December 15, 2025

Chickens in a backyard in San Francisco, California. Avian influenza infections in humans are currently very rare in the U.S. (Photo credit: Justin Sullivan/Getty Images)

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• Animal Ag
• Food Safety
• Urban Agriculture

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ASeattle-area senior who was raising a backyard flock of mixed domestic birds died from the H5N5 strain of avian influenza last month after being hospitalized for complications related to the virus. Health officials haven’t released further information out of respect for the man’s privacy. But he had underlying health conditions—just like the Louisiana senior who died following exposure to sick and dead backyard poultry last year (albeit from a different strain, H5N1).

“You should have a coop that has some kind of physical separation between your birds and the outside environment.”

Having that level of biosecurity where the birds are [entirely] enclosed from the outside environment is very rare, unfortunately. A lot of people still use chicken wire to fence off their coops. Chicken wire keeps chickens in, but it doesn’t keep rodents and other predators out, and wild birds can squeak through [the holes]. I recommend that people use hardware cloth, which is thick, typically galvanized steel, quarter-inch fencing that you can bury and wrap around things, and it makes it much harder for wildlife to get in.

I’ve [also] seen a few people with netting in their coop run on the top. That means it’s much easier, especially for anything flying, to get into the coop, and when there’s spilled feed, you’re just inviting wildlife to come in.

Do you recommend against allowing chickens to range freely, outside the coop?

People have backyard birds for a lot of reasons, including they want to allow the birds to live a natural life and roam around. That’s where you’re threading this needle between [quality of life] and the risks of disease transmission.

I’ve worked with enough backyard poultry enthusiasts to know that if I told them to do [that], they probably wouldn’t listen to me. So, I’m a big proponent of not making perfect the enemy of the good and following the spirit of what [backyard poultry raisers] want. With that understanding, we can create runs and coops that allow chickens to be chickens  but also reduce potential interactions with wild animals.

What are other key biosecurity measures? 

In addition to wearing protective gear, like clothing and boots that are dedicated to your coop, you should wear a mask and some kind of eye protection. We have seen some really bad eye infections in dairy workers.

It’s also good practice to be vaccinated for human flu. What we don’t want to happen are these co-infections where you have a human and an avian influenza intermingling in respiratory cells. That’s when you can get highly infectious, highly pathogenic viruses evolving that are novel to the human immune system.

The other thing I encourage people to do is have a plan—that is, a veterinarian to call—if something bad happens to their birds. When people go to feed stores and buy chicks, there isn’t this culture of, ‘we need to get a vet now.’ If you have a puppy or kitten, everyone thinks about that.

What are signs of bird flu that people should be looking for in their birds? And what should you do when you see those signs of illness?

Figure out what is normal in your flock, a daily sense of their behavior. That way when something weird happens, you’ll know whether it’s abnormal. The biggest one is a sudden drop in egg production. You’ll also see coughing or sneezing, mucus coming out of orifices, odd neurologic behavior and twisting of the neck, swelling in the head area, or diarrhea.

“If it is bird flu, you’d want to act quickly and protect your neighbor’s flocks, and if it’s another illness, you’d want to take care of that anyway.”

Say you woke up tomorrow and had one egg instead of five, and you noticed a couple chickens were sneezing and coughing and seemed really lethargic. You’d want to separate those birds and call a vet with poultry expertise. The vet can help you with next steps, including how to care for your sick birds in the event they have an illness other than bird flu.

Unfortunately, you don’t want to take sick birds to your vet because you could be exposing many other animals and humans to avian influenza. If you want someone to examine your birds, call your state’s department of agriculture or sick-bird hotline and they will send someone out. Bird flu testing is mostly done post-mortem. If it is bird flu, you’d want to act quickly and protect your neighbor’s flocks, and if it’s another illness, you’d want to take care of that anyway.

If your sick birds are not examined by anyone, and two or three die, submit the dead birds to a diagnostic lab. You can do that yourself or ask the state department of agriculture to do it. You want to act quickly to prevent possible spread of the virus.

Most states, especially those with veterinary schools, have diagnostic labs that are run through universities. In California we have the California Animal Health and Food Safety Lab, where for a very nominal fee, about $20, you can submit birds and they’ll do an animal autopsy.

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What should you do if bird flu is detected in your birds that died?

If it is found to be high pathogenic avian influenza, unfortunately the entire flock will need to be euthanized, because the assumption is that it will spread throughout the entire flock.  As a veterinarian, it’s the last thing I want to do, but that’s how we stop the disease from spreading. There are a lot of unknowns, and we don’t have the resources or, frankly, the knowledge to do and interpret serology and virus isolation data on every bird to figure out which has an immune response—and then do that every six weeks.

Another concern [with letting the flock live] is, if you bring in new birds, will you have asymptomatic spread—because now those birds that survived are somewhat immunized? And when they die eventually, will you have seeded the environment with virus?  The virus can get a toehold in a region. And It’s not just the birds you worry about, but feral cats, domestic cats, any kind of wildlife that might be exposed to those domestic backyard birds.

Cats seem to be uniquely sensitive to the virus. If you have indoor-outdoor cats that are exposed to the same environment that the chickens are, you’re lining yourself up for some potential transmission to humans.

What factors contribute to the spread of bird flu in backyards? 

Many [backyard poultry owners] don’t have veterinarians, or knowledge of—or interest in— participating in any kind of surveillance system, and the states and the feds have limited resources. The last thing they want to do is increase surveillance on backyard facilities that probably average five chickens, instead of working with these large producers that have millions of birds.

There’s also this sentiment that they’re “just chickens.” When birds die, a lot of people don’t do anything. People are probably under-submitting samples from dead birds. In California, we get a couple hundred submissions a year from backyards.

Another part of the problem is that for some people, these are pets. Someone might say, I’m not going to tell the state or the USDA what happened, because they’re going to euthanize my birds and these other two are fine.

Overall, how worried are you about bird flu in backyard flocks?

It’s my job to worry. I don’t like the mentality that ‘It’s just a few infections.’ Small things, especially when it comes to infectious diseases, are much easier to deal with than big things. At this point, backyard poultry owners should be using a lot of the same [practices] that the commercial poultry folks use to protect further spread and themselves.

What I tell people is that there is a shared responsibility in raising our birds with good husbandry and biosecurity practices. If they get sick and we start seeing a sudden drop in egg production, that’s when we need to reach out to our veterinarians to figure out what’s going on. The quicker we diagnose disease, as backyard poultry owners, the less likely it is for that disease to spread.