What is Avian Influenza & How to Prevent It
by Alexa Lehr | The Pioneer Chicks | July 23, 2024
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The bird flu…. the news makes it sound rather scary, but a better understanding of this avian virus will help you evaluate the risk it might pose to your homestead flock. Avian influenza, or the bird flu, is highly contagious and can have devastating results for entire flocks. It was once thought that small backyard flocks were contributors to the seriousness of the virus, however, it has since been discovered that the spread of the virus is more on the part of improper management in the commercial poultry industry. Once you realize how the virus is spread and the two variances of the virus, you will be able to take the proper preventative practices that can help protect your flock and keep the avian flu from being a serious threat on your homestead!

What is Avian Influenza?

Avian influenza is a viral infection that infects both domestic and wild birds. It can also be called the avian flu, AI, or bird flu. There are two variances of avian influenza: high-pathogenicity (HPAI) and low-pathogenicity (LPAI). The high-path variance of the flu is not as common as the low-path variance but it is a lot more fatal. Both the high-path and the low-path flu are caused by various orthomyxoviruses. These are the same kinds of viruses that cause the flu in humans, horses, pigs, dogs, and other animals.

The type of orthomyxovirus that causes avian influenza is know as the type influenza A virus. The variances in the type A virus is further divided into subtypes according to the combination of proteins they contain. Type A viruses contain two types of proteins: hemagglutinin (H) and neuraminidase (N). There are 16 known H proteins identified as H1-H16 and 9 known N proteins identified as N1-N9. That means there can be up to 144 different strains of the avian flu. The strains are identified based on the proteins they contain, for example, H1N1 is a strain of the bird flu.

The different strains of avian influenza are then categorized as low-path or high-path depending on the severity of the infection. Most avian influenza viruses are low-path. However, some low-path viruses can mutate into high-path viruses as they spread through numerous chickens.

How Avian Influenza Spreads

The avian flu virus is spread through direct contact with wild or domestic birds who have the virus. There are certain wild species of birds that are natural hosts for the virus but who show no symptoms. Aquatic birds, shorebirds, and waterfowl are all know as natural hosts for the avian influenza virus. As a host, they can spread the virus to each other, to other bird species, and even to mammals. Chickens are not natural hosts of the virus but they can become infected when exposed to the virus.

Chickens who are confined or who live in crowded living conditions are the most vulnerable. Avian influenza infections can spread rapidly through confined flocks and are often more fatal in large flocks since low-path infections can mutate into high-path infections when spreading through large numbers of birds.

Both the high-path and the low-path strains can be spread by contaminated equipment, clothing, or shoes. Insects or rodents can also carry the virus on their feet and fur. Bodily discharges such as feces or respiratory discharge can transmit the disease or contaminate litter, feed, or water. If a bird becomes infected and recovers from the infection (common with low-path virus infections), the bird remains a carrier of that virus for life.

Symptoms of the Avian Flu

High-path avian influenza will come on suddenly and spread rapidly through both large and small flocks. A high-path infection lasts about 1-3 days. If sudden death doesn’t take place right away, symptomatic birds will usually die within 48 hours. Here are some symptoms of a high-path flu outbreak in birds of any age:

• sudden death
• decreased activity
• lethargy
• decrease in food & water intake
• swollen & dark facial features
• swollen & red legs
• soft or no-shell eggs
• rapid drop in laying
• respiratory distress: coughing, sneezing, rales
• bloody discharge from nose/mouth
• greenish diarrhea
• quivering muscles and/or twisted neck
• partial paralysis (inability to stand)

Low-path avian influenza is often asymptomatic and it is less fatal. In fact, your flock may have a low-path strain and hardly exhibit any symptoms. Mortality rates for low-path avian flu rarely exceed 5%, with most fatalities occurring in young birds who don’t have a strong immune system yet. Here are some symptoms of a low-path flu infection:

• ruffled feathers & lethargy
• coughing
• sneezing
• rattly breathing
• rales
• watery eyes
• nasal discharge
• decrease in food & water intake
• sometimes diarrhea
• decrease in laying

How to Diagnose the Avian Flu in the Homestead Flock

The only way to accurately diagnose the avian flu virus is through laboratory testing. Laboratory diagnosis of the virus can identify what strain of virus is causing the infection. However, high-path avian flu is usually diagnosable by its sudden onset and high mortality. High-path avian influenza can have a 100% mortality rate and even if there are survivors, those birds must be eliminated since they will be carriers of the virus for life.

In a postmortem examination, birds with high-path avian flue may have hemorrhages (reddish/brown spots or blotches) in the digestive tract, ovaries, and in any abdominal fat. There may also be yellowish fluid beneath the skin of the face, swollen blood vessels, and a loose gizzard lining. Birds who die suddenly usually have little to no postmortem evidence.

External symptoms can clue you into an infection, but many of the avian flu symptoms also overlap with other diseases. The symptoms can range from respiratory distress to digestive symptoms, from poor reproductive health to neurological symptoms. The most common and significant symptom of the high-path avian flu is sudden and rapid deaths.

Low-path avian flu is nearly impossible to diagnose without a laboratory. If the chickens exhibit any symptoms at all, they can also be signs of other diseases such as chronic respiratory disease, infectious bronchitis, or Newcastle disease. High-path avian flu can be mistaken for acute fowl cholera, velogenic Newcastle disease, severe heat exhaustion, or acute poisoning.

How to Treat Avian Influenza

Unfortunately, there is no treatment for either high-path or low-path avian influenza. In the case of a high-path outbreak, all the infected birds must be quarantined and destroyed. A thorough cleaning and disinfecting of the living spaces must follow the extermination to prevent any future flocks from becoming infected.

Low-path outbreaks will sometimes spread through a small homestead flock un-noticed. Once it has run its course, the birds in that flock will have built immunity to that particular strain of the virus and will be less likely to be infected again. However, any new birds added to the flock are susceptible to the virus since the recovered birds remain carriers of the virus. The whole flock can also be susceptible to a different strain of the flu that they haven’t built immunity to yet.

Helping the birds in your homestead flock build up strong immune systems can be helpful for preventing low-path flu viruses from mutating into high-path strains. Use immune-boosting natural supplements and feed your flock a balanced diet to help them stay healthy for warding off disease!

High-path avian influenza is a reportable disease. Low-path strains H5 and H7 are also reportable since they can become highly pathogenic. A reportable disease is one that a veterinarian or state diagnostic laboratory HAS to report for the safety of the poultry industry or human health. The Animal & Plant Health Inspection Service (APHIS) or the Office of International Epizootics (OIE) are two agencies that must be notified about a reportable disease.

Certain strains of high-path avian influenza have been known to infect humans. Take proper protection and sanitary measures when dealing with a flock that has been infected with high-path avian flu. If you start to feel flu-like symptoms, contact your doctor immediately.

How to Prevent Avian Influenza

Taking proper biosecurity measures when caring for the homestead flock can help prevent the risk of avian influenza! The main way to prevent the bird flu in your flock is by minimizing their exposure to potential carriers of the virus. Here are some good biosecurity measures to take for preventing the bird flu:

#1. Reduce Contact with Wild Birds

Avoid attracting wild birds near the chicken coop or in areas where your flock forages. This is particularly important for areas that might attract waterfowl, who are natural carriers of the virus. Don’t feed the wild birds near the chicken coop or yard. If possible, keep your flock’s feeder inside to prevent attracting wild birds from entering the chicken coop enclosure.

Personally, I feed my chickens in their outdoor enclosure. I know that some wild birds (mostly juncos and sparrows) clean up the spilled feed in the enclosure, but songbirds are less of a threat than aquatic birds. I also live in the woods, where the wild birds have limited contact with other aquatic birds and are less likely to transmit the disease. However, migratory birds can come in contact with carriers of the virus and become carriers themselves.

#2. Minimize Puddles & Standing Water

Not only can standing water host a horde of other harmful bacteria and pathogens, it can also attract wild waterfowl. Since waterfowl are natural hosts of the avian flu, you will want to prevent attracting any wild waterfowl to your homestead. Fill in depressions or holes that can collect standing water. I find that having a covered chicken coop enclosure that has a thick layer of composted straw over sand as the litter is an effective way to keep a dry and clean enclosure.

I also live in a swampy section of woods, so my birds are routinely exposed to standing water when they forage, especially during the spring and early summer. These swampy areas are not large enough or accessible enough to attract any significant populations of waterfowl (occasionally a wood duck or two) so I feel fairly safe letting my flock forage freely despite the swampy environment.

#3. Keep a Closed Flock

Keeping a closed flock is one of the best ways to prevent disease and illness in the homestead flock. A closed flock is one that is not exposed to other domestic poultry that have not been raised on the same property. Examples of keeping a closed flock would include not adding mature poultry or chicks from outside sources (hatcheries, farms, other homesteads) and not taking birds to poultry shows or swaps. Essentially, a closed flock contains birds who have been raised on the same property and who have never left the property.

Once you get an established homestead flock, you can keep it closed by raising future generations of poultry right from your own flock! All you need is a rooster (or two) and an incubator or a reliable broody hen. Hatch eggs right from your own homestead flock to replace aging hens or any losses in the flock. That way you don’t have to buy hatchery chicks or birds from other sources!

Keep in mind, if you raise a small flock, it may be a good idea to outsource the cock every few years to prevent inbreeding. You can also minimize the affects of inbreeding by keeping two or three separate breeding flocks and rotating the roosters between the different flocks. You can also keep this breeding principle in mind: breed daughters to fathers and sons to mothers, never brothers to sisters.

#4. Quarantine New Birds

IF you do have to add new birds to your homestead flock who have not been raised on your property (such as in the event of outsourcing a breeding cock), you will want to keep the new birds quarantined for at least 3-4 weeks. Quarantining means keeping the new birds away from your flock with no exposure to each other at all. Care for your flock first, then tend to the new birds. Watch the new birds for signs of illness or disease before integrating them into your flock.

Quarantining is more important for maturing or adult poultry versus chicks. When you outsource chicks, you will more than likely be brooding them away from your adult chickens for at least 4 weeks while they need supplemental heat in the brooder. Baby chicks are also less likely to be carriers of the virus since they more than likely haven’t been exposed to the virus and the virus cannot be passed down genetically.

#5. Don’t Share Equipment

Lastly, reduce the chance of exposure to the virus through contaminated equipment or clothing. Any piece of equipment or clothing that gets feces, nasal discharge, or salvia on it from an infected bird can transmit the virus to a healthy flock. Don’t share chicken keeping equipment with other homesteaders and avoid buying second-hand poultry equipment from Facebook Marketplace, eBay, Craigslist, or any other second-hand source.

You will also want to be careful about your clothing and footwear. Have a pair of chore boots that you use around your homestead and that never leave your property. If you go to another place that has poultry, have a different pair of boots that you use for off-farm purposes. The same principle applies if you have other homesteaders come visit your flock. Have them wear different shoes that haven’t been exposed to outside sources of poultry. If you work or volunteer in situations where you are handling lots of different birds, make sure you change your clothes before tending to your own flock.

Avian influenza is a hazardous poultry disease that has been around for over a century. The disease has become more prevalent in the recent years as highly-pathogenic variances of the virus start cropping up in large-scale poultry operations. You can prevent the avian flu from becoming an issue on your homestead by practicing good biosecurity measures. Reducing exposure to potential carriers of the virus is the best way to keep your flock safe. With proper management, a balanced diet, and natural care, your homestead flock can stay healthy and productive!

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