The following provides advice to organic poultry producers on avian flu, including steps for risk assessment and key symptoms (including pictures of infected birds).
Avian influenza (or bird flu) is a notifiable disease and, as such, you must contact the local divisional veterinary manager of Animal Health if you suspect the disease is on your farm. Your own vet will do this if you let them know of your suspicions.
There have been very few incidences of the high pathogenic disease in the UK. However, organic farmers should take the threat very seriously. Although there is more and more evidence that the primary means of transmission is through the trade and movement of birds and poultry products, wild birds can still be a vector. As organic birds are kept outside they are potentially highly vulnerable to infection should it be transmitted by this latter route. The disease is also particularly important because humans can potentially acquire the disease through contact with live, diseased birds. However, the World Health Organisation (WHO) and the Food Standards Agency (FSA) state that poultry products are not a likely source of infection.
Reducing the risks
By making a few minor changes to your current farm practices you can significantly reduce the threat from avian influenza (AI). As organic poultry producers are already aware of the need for extreme vigilance of potential threats and challenges to their birds, these additional measures should amount to no more than an extension of existing surveillance and biosecurity practices. There are two key areas for immediate action:
A) Constantly re-assess the risk by following Defra’s advice:
The Soil Association strongly recommends that you make a fresh risk assessment of the challenges to your flocks in line with this advice, which should also consider the risk to human health. For Defra’s advice see www.defra.gov.uk, and follow the ‘quick links’. Alternatively, call the Soil Association food and farming department on 0117 914 2400 and ask for a print out. Basic biosecurity measures should include disinfectant foot dips for farm visitors and ensuring that potential contamination from faeces is not carried on vehicles, for example.
B) Prepare a contingency plan in the event of increased risk or an actual outbreak:
In the event of increased risk or an actual outbreak of AI in the UK, statutory measures will require that all birds within a specified restricted zone around the outbreak will have to be isolated. This isolation can be achieved by shutting birds in their houses and not letting them out to range. However, unless adequate contingency plans are in place, housing of the birds within a short time-frame could have major welfare implications. Farmers must therefore be prepared for this. See the separate Soil Association briefing, Advice if birds must be kept in house’ for ways to minimise any welfare risks.
The Soil Association has also worked with Defra to get agreement that if the welfare of birds would be seriously compromised or if there are other reasons why they cannot be housed they can be isolated by netting part or all of the free-range area to stop wild birds mixing with domestic birds. This ensures that organic birds can still have some outdoor access, albeit limited, whilst they are isolated. The briefing paper noted above also has information on how this can be achieved without compromising biosecurity. The need for isolation should only arise in the event of an outbreak of high pathogenic AI.
Sources of infection
When undertaking a risk assessment on your holding you should pay particular attention to the following potential sources of infection:
- Water courses, lakes, rivers and ponds, and so on present an important risk area, as the virus is known to live in waterfowl without showing clinical symptoms. The virus can also survive relatively well in water, when compared with faeces. Large, dense populations of wild birds obviously carry risks. Assess where you can reduce contact between poultry and wild birds in these areas
- Visitors – both humans and the four legged kind – should be monitored and contact with poultry kept to a minimum, wherever possible
- Try to restrict the contact between poultry, waterfowl and pigs. Pay attention to both direct contact, as well as indirect. Remember pigs can act as a host and accelerator of AI but are not actually affected
- Observe changes to the wild bird population, particularly pheasants. If unusual mortality occurs contact your local divisional veterinary manager as soon as possible. Although the risk of introduction by migratory birds is very low, stock near wild waterfowl populations can be at risk. For the last couple of years, Defra has been conducting surveillance on migratory and resident wild waterfowl as well as investigating ‘die outs’ of wild birds in specified high risk areas. For more information on when and how to report these deaths visit www.defra.gov.uk/animalh/diseases/notifiable/disease/ai/wildbirds/index.htm#reporting
Your vet and local Defra office can provide further advice and assistance on carrying out a risk assessment and your health plan. Your local ornithological society or the RSPB can also help
Symptoms
While the Soil Association hope that producers will never encounter infected birds, it is important to be aware of the disease symptoms.
A wide variety of symptoms can occur when birds are infected with AI, and birds can often die without any apparent sign of disease. In general, sudden death with high mortality and no preceding signs should raise alarm bells for producers. If you have any suspicions about an unusual poultry diseases you should contact your vet so that laboratory investigation can be carried out as quickly as possible. Other symptoms of AI include:
Decreased feed consumption
- Drop in egg production, and the last eggs laid after the onset of illness are frequently without shells
- Oedema (swelling) of the head, the neck and around the eyes
- Cyanosis (blue colouring due to poor circulation) of the comb and wattles
- Plasma or blood vesicles on the surface of the comb with dotted haemorrhage
- Dullness and lack of appetite
- Respiratory distress
- Diarrhoea, which begins as watery bright green and progresses to almost
totally white
- Marked depression
- Ruffled feathers
- Excessive thirst
- The legs, between the hocks and feet, may have areas of diffuse haemorrhage.
Death may occur within 24 hours of the first signs of disease, frequently within 48 hours, or be delayed for as long as a week. Some severely affected hens may occasionally recover. In broilers, the signs of disease are often less obvious. Severe depression, lack of appetite, and a marked increase in mortality are usually the first abnormalities observed. Oedema of the face and neck and neurologic signs, such as torticollis and ataxia, may also be seen.
The disease in turkeys is similar to that seen in layers but it lasts two or three days longer, and is occasionally accompanied by swollen sinuses. In domestic ducks and geese the signs of depression, lack of appetite, and diarrhoea are similar to those in layers, although frequently with swollen sinuses. Younger birds may exhibit neurologic signs.
- Reference material
The following recommended websites provide useful advice and information on avian influenza in terms of both animal and human health:
World Health Organisation
Defra
Health Protection Agency
Clinical Symptoms of Avian Influenza
The following images provide examples of the key clinical symptoms of avian influenza (AI). They do not provide all the clinical signs. Consult your vet if you are at all concerned.
 
Oedema of the wattle.
 
Cyanotic comb of infected Infected comb.
(Healthy bird on the right).
 
50 week old bird, haemorrhage, Hock, leg swelling and haemorrhaging.
dead tissue, swelling on comb and
wattles seven days after infection via
inhaled AI.
For further information please call the Soil Association food and farming department on 0117 914 2400
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