FREE Delivery On All Orders Over £250 - Conditions Apply

Supplying the poultry industry for three decades

Avian Flu aka Bird Flu – A Comprehensive Guide

Rowan Burgess |

The UK is experiencing one of the worst outbreaks of bird flu. Crucial to protecting birds and preventing the transmission of this disease is information. 

There is currently no vaccination against avian flu, so control zones and careful observation is the only way to halt its progress. Because the virus is also present in and spread by wild birds, there is a considerable challenge ahead.

Knowledge is power in the spread of bird flu, so it’s crucial to understand the disease and how it is transmitted. Read this comprehensive guide to learn the best measures to prevent it and protect poultry.

What is Avian Influenza?

Avian Influenza, also known as Bird Flu, is a disease caused by infection with the avian influenza Type A viruses. These viruses naturally live within the wild bird population and spread to infect domestic and farmed poultry and other animal species.

Avian influenza breaks down into two types, highly pathogenic and low pathogenic.

Low Pathogenic vs Highly Pathogenic

Highly pathogenic avian influenza (HPAI) has severe symptoms, but birds infected with the less serious strain of bird flu, called low pathogenic avian influenza (LPAI), may show hardly any or no signs of infection.

LPAI sometimes causes mild breathing problems, which can appear as symptoms of something else. Testing is the only way to make a definitive diagnosis.

To make matters more complicated, some species, such as swans, geese and ducks, can carry the virus without showing any signs of illness.

Preventing the Transmission of Avian Flu

Avian Influenza is a global disease that occurs naturally in wild birds. Scientists consider shorebirds and waterfowl the natural reservoir for multiple avian influenza viruses.

As birds migrate, they can spread disease around the four corners of the globe and transmit it to domestic birds. Migration is impossible to control. 

Wild birds were relatively unaffected by avian flu, but spill-back has occurred from domestic and farmed poultry flocks, negatively affecting healthy birds who now succumb to the disease.

International trade and globalisation have accelerated transmission. No longer is poultry kept in small numbers and slaughtered and eaten locally.

Farming of birds takes place in large numbers with farming methods that make any disease harder to control. Once avian flu is present, it’s almost impossible to prevent it from spreading within big groups of poultry housed inside.

Avian flu’s transmission can be limited if not halted by close monitoring of flocks, culling where the disease is endemic, and preventing the movement and sale of birds within defined disease control zones.

Everyone can play a part in preventing transmission. Local authorities should encourage the public to report sick or dead wild birds by calling the Defra helpline with specific sightings. These include a single dead bird of prey or owl, three or more dead waterfowl or gulls, or five or more dead birds of any species. 

Some of these birds will be collected and tested to help map a disease pattern. Defra also instructs hobby keepers of small domestic poultry flocks to house these birds indoors.

Detecting and Responding to an Avian Bird Flu Outbreak

Close monitoring of birds, whether they are domestic or commercially farmed, is essential to be able to spot symptoms early. Most vets work closely with bird owners to provide regular information, advice and support.

What are the Symptoms of Avian Bird Flu in Poultry?

Symptoms of Avian Flu will depend upon whether the birds have contracted HPAI or the less obvious low pathogenic strain, which can be much harder to spot.

Common symptoms include:

  • Runny or closed eyes
  • Loss of appetite
  • Lethargy and depression
  • Lack of coordination and dragging the legs
  • Resting or lying down more than usual
  • Unresponsiveness
  • Swollen head
  • Twisting of the head and neck
  • Swelling and discolouration to the comb and wattles
  • A sudden change in water consumption which may be an increase or decrease
  • Shaking of the head and body
  • Loose, watery or discoloured droppings
  • Wing droop
  • Breathing difficulties such as gaping, coughing, rattling, sneezing or gurgling
  • Fever
  • Low or no egg production

What To Do if a Bird Flu Outbreak is Suspected?

Swift action is essential in the event a bird flu outbreak is suspected.

  1. Report the outbreak to the Animal and Plant Health Agency (APHA) – your vet may do this for you. Bird flu is a notifiable disease, so you're breaking the law if you don’t report it.
  2. The APHA usually need to investigate further and will send a veterinary inspector to your premises.
  3. Before their arrival, the APHA duty vet will tell you what restrictions you must follow, including imposing a quarantine so that no birds or other animals susceptible to the disease can move on or off the premises. The quarantine can also extend to equipment and vehicles, essentially anything that could transmit disease if it left the site.
  4. A temporary control zone may be placed around the premises to help stop the disease from spreading.

What Role Does UKHSA Play?

The UK Health Security Agency is a new organisation officially launched on 1 April 2021 to plan for, protect against and prevent external health threats to every UK citizen.

UKHSA offers a permanent fixture that actively monitors and protects the UK population from any external threat to health by using strategic planning and collaboration with academia, industry and local communities.

Health threats include chemical, biological, radiological and nuclear incidents and other hazards such as the risk to humans from diseases like avian influenza. 

The Covid pandemic prompted the development of this organisation. The UKHSA monitor the progress of avian flu to spot any early evidence that the virus may spread from birds to people, although this isn't happening.

The UKHSA will assess those who have been in contact with a confirmed or suspected case of avian flu and will follow up and take action if required.

Protecting Healthy Poultry and Minimising Losses

Protecting healthy poultry will guard the birds against the disease and its transmission while minimising financial loss in commercial flocks. Here are some of the most important measures.

Identifying the Disease

Commercial and domestic poultry keepers must recognise the symptoms of the disease so they can take early action if they suspect bird flu. 

Effective monitoring requires close collaboration with your farm or private vet, who will also be familiar with other disease outbreaks in your local area.

Follow DEFRA Guidance

The Department for Food and Rural Affairs offers advice and guidance on housing birds – currently, all birds in certain identified disease zones must remain indoors. All vets who treat poultry are up to date with the latest regulations.

Avoid Poultry Farms

Staff on poultry farms are very aware of the importance of biosecurity and disinfecting their clothing and vehicles before going on and off-site to prevent disease transmission. This is made possible through the implementation of modern biosecurity solutions, such as foot dip buckets and pressure sprayers.

The public should avoid poultry farms and areas around them. Domestic keepers must be aware of visiting other premises that house birds or conduct poultry sales.

Minimising Financial Losses

The current avian influenza outbreak is one of the worst recorded, and some farmers have been badly affected by poultry losses.

Compensation is available for farmers with flocks affected by bird flu, but this only extends to healthy birds culled by vets from the APHA. Birds showing signs of the disease or who have already died do not qualify for compensation.

The NFU (National Farmers Union) are campaigning to change the rules as large numbers of birds can die between the time of identification of the virus and the point at which the flock is culled.

In the meantime, shielding poultry flocks and farms and early reporting for any signs of the disease are the best ways to protect against financial loss.

Frequently Asked Questions

Are There Any Vaccines or Treatments for Avian Bird Flu in Poultry?

The vaccination of poultry and captive birds is not a routine control measure for this disease and is largely restricted by legislation with only a few exceptions. Currently, early reporting, good biosecurity and culling are the most effective ways to protect against and control bird flu.

Can Humans Get Avian Influenza?

Transmission of bird flu viruses to people is very rare; however, occasional outbreaks have occurred. Symptoms in humans range from none to mild, severe, and sometimes fatal. H5N1 is the strain responsible for most serious human illnesses, including the highest mortality rate.


The UK is experiencing one of the worst outbreaks of avian influenza. However, everyone can play a part to protect farmed and domestic poultry and the wild bird population.

You can rely on Dalton to help protect your birds with a range of quality products for feeding, biosecurity and comprehensive management to promote a healthy flock. We are your trusted partner in the fight against avian influenza.