I Have a Backyard Chicken Flock. Should I Worry About Bird Flu?

If you’re a backyard chicken owner (and even if you’re not), you’ve likely heard about Avian Influenza (AI). Commonly referred to as bird flu, it’s a highly contagious viral disease affecting domestic poultry, wild birds, and, in some cases, mammals … including humans.

The recent rise in Avian Influenza cases has raised concerns, and if you’re anything like us, you have questions. How does AI spread? What risks does it pose? What actions can we take if an animal shows symptoms, and how can we protect our flocks and households? We asked a few experts to shed some light and cut through the science.

How Does Bird Flu Spread?

First, Avian Influenza is caused by Influenza A viruses that are primarily transmitted through direct contact with infected birds, their feces, or affected surfaces. One of those is Highly Pathogenic Avian Influenza (HPAI), which is a very severe strain.

Dr. Michelle Hawkins, VMD, Director of the California Raptor Center and Professor of Avian and Exotic Medicine and Surgery at UC Davis School of Veterinary Medicine, explains that the disease spreads through respiratory transmission, fecal matter, and contaminated objects like clothing, shoes, and even vehicle tires. Waterfowl, such as ducks and geese, are known carriers and natural hosts of the disease. In fact, they can spread the virus without even displaying symptoms.

“Influenzas concentrate within waterfowl, and they’re often shed by waterfowl,” says Dr. Hawkins. “Most of them have never shown clinical signs of the disease but have carried and then spread it into the environment because it’s passed in the feces. And waterfowl have a lot of poop!”

Dr. Hawkins emphasizes that Avian Influenza can be transmitted through aerosolized particles, meaning infected birds shedding the virus can spread it through the air.

“The $50 veterinary word is ‘fomite,’” she tells us. Fomites play a crucial role in transmission, as people inadvertently carry the virus from infected environments to their flocks. Cases such as a Pennsylvania outbreak in the 1990s highlight how AI can quickly spread between farms through shared equipment and personnel. 

“There was an Avian Influenza outbreak in Pennsylvania when I was in vet school,” explains Dr. Hawkins, “where a company owned chicken and turkey farms. Both farms got infected because of trucks going back and forth between the two facilities. So, we know it can be transferred.”

So, What are the Risks to Humans and Pets?

Bird flu is classified as a zoonotic disease, meaning it has the potential to jump from birds to mammals. Dr. Kay Russo, a representative and member of the American Association of Avian Pathologists, notes that AI has already had a few significant spillover events, infecting mammalian species like domestic cats, who contracted the virus after consuming contaminated raw milk or infected birds.

“It seems cats are really susceptible compared to dogs,” says Dr. Hawkins. 

While human infections are rare, there have been fatal cases in past outbreaks, particularly in Asia.

Dr. Hawkins warns that when multiple strains of Avian Influenza mix within an animal, they can re-assort their genetic material, potentially creating new strains with an increased risk of infecting humans and other mammals.

“That re-assortment may very well be why we’re having all these different species affected now,” says Dr. Hawkins. “Last year in Patagonia, where elephant seals go to pup and rebreed, I don’t believe any pup survived last year. That was totally unexpected. They were worried about the penguins; suddenly, it was the elephant seals.”

This is why there’s so much concern that AI will jump into humans. The current strains circulating in the U.S., including H5N1 and H5N9, are being closely monitored for their potential to evolve into a more dangerous variant.

What Are the Symptoms of Avian Influenza?

Avian Influenza presents with a range of clinical signs, making it difficult to distinguish from other poultry diseases. It also depends on the animal. Cats, for example, tend to have a high rate of neurological symptoms. Cows, on the other hand, carry the disease in their milk. “They get some weird milk, and it’s taking about 30 days to clear them of it,” explains Dr. Hawkins. “But they are clearing it, which we didn’t know would happen.”

As for chickens and other poultry, Dr. Russo highlights the following symptoms:

• Sudden and high mortality rates within a flock
• Neurological signs, including twisted necks, tremors, and paralysis
• Decreased egg production and abnormal eggs with soft or misshapen shells
• Respiratory distress, including sneezing and nasal discharge
• Swelling of the head, legs, and face
• Purple discoloration of the comb, wattles, and shanks
• Diarrhea

Backyard flock owners should closely monitor their birds for these signs and take immediate action if they suspect AI. “Highly Pathogenic Avian Influenza is very contagious between chickens and can kill a flock within a matter of a few days of initial exposure,” says Dr. Russo.

What Can You Do if Your Chickens Show Symptoms?

If a backyard chicken exhibits AI symptoms, immediate action is necessary to protect the rest of the flock and prevent further spread. Dr. Russo advises taking the following steps:

• Isolate Sick Birds: Move affected birds away from the rest of the flock.
• Wear Protective Gear: To reduce the risk of exposure, wear gloves, masks, and eye protection when handling birds.
• Report to Authorities: To report suspected cases, contact a veterinarian, USDA veterinarian, or the state veterinarian’s office. 
• Avoid Consuming Eggs or Meat: Infected birds should not be consumed, as this could lead to viral exposure and human infection.
• Follow Testing and Control Measures: If AI is confirmed, flocks are typically euthanized to prevent further transmission.

Because poultry shed high amounts of the virus before death, containment through euthanization is often the most effective way to prevent widespread infection. Dr. Hawkins acknowledges that the prospect of culling an entire flock is distressing for backyard chicken owners. 

Dr. Russo echoes that sentiment, saying, “If testing reveals that your birds are positive for HPAI, the virus is controlled through euthanizing your flock. It is not lost on me that this is a difficult situation for bird owners who care deeply for their birds. But it is necessary to protect you and your neighbors, given the nature of this disease.”

What Preventive Measures Can We Take for Our Backyard Flocks?

Preventing HPAI in backyard flocks requires strong biosecurity practices. Dr. Russo and Dr. Hawkins provide the following key recommendations:

• Have a Veterinarian Monitor Your Flock: Having a vet check your flock every year can help address questions and concerns about health and management. If you are concerned about influenza in your flock, your veterinarian can also conduct a flu test.
• Limit Wild Bird Exposure: Fence in your chickens and use netting, tarp, wood, or another protective covering on top of the enclosure to prevent contact with wild birds and their droppings. This is particularly important in areas that fall along the major flyways for migratory birds.
• Eliminate Bird Feeders and Baths: These attract wild birds that may carry the virus.
• Secure Housing and Reduce Entry Points: Mice and other small animals have been found carrying the virus in high-risk areas.
• Change Clothing and Shoes: Wear dedicated footwear (such as disposable booties) and clothing to prevent introducing contaminants. “Change your shoes and clothing before and after tending to your birds,” shares Dr. Russo. 
• Wash Hands Before and After Handling Birds: Proper hygiene minimizes virus transmission.
• Restrict Visitors: Limit access to your flock, especially for individuals who work with poultry.
• Quarantine New Birds: Keep newly acquired birds separate for at least 30 days before integrating them into the flock.
• Maintain Cleanliness: Regularly disinfect waterers, feeders, and housing areas with an effective disinfectant like bleach.
• Keep Different Species Separated: Chickens and waterfowl should not be housed together, as ducks are more likely to carry AI asymptomatically. Additionally, keep cows and chickens separate, as they both host the virus.
• Limit Outdoor Access: While it’s not always feasible to bring a flock of chickens indoors, Dr. Russo says, Limiting outdoor access is probably the very best thing you can do for your birds until regional infections begin to subside.”  

How Can We Protect Our Domestic Pets and Families?

Pet owners should take additional precautions, as AI can infect domestic animals, particularly cats. Dr. Russo and Dr. Hawkins recommend:

• Keeping cats indoors to prevent them from consuming infected birds
• Avoiding raw milk and raw meat diets, as AI has been detected in these products
• Practicing strict hygiene, especially if handling both poultry and pets
• Showering and changing clothes after exposure to high-risk environments

While HPAI vaccines for poultry are unavailable in the U.S., researchers are exploring potential solutions. The best defense against AI for humans is minimizing direct contact with infected birds, staying vigilant, monitoring your birds for symptoms and behavioral changes, following safety guidelines, and taking proactive biosecurity measures.