Health of poultry, bird-specific diseases and infections, and the responsibility to report suspected outbreaks.
All owners and keepers responsible for animals - including farmed poultry - have a duty of care under the Animal Welfare Act (2006). This is to ensure their animals are provided with a suitable environment and diet, so as to be free to exhibit normal behaviour patterns, to be housed with, or apart from, other animals (if applicable) and to be protected from pain, injury, suffering and disease.
This guide deals specifically with the health considerations of poultry livestock which may be covered under separate regulations, but for purposes of this guide includes chickens (including bantams), turkeys, ducks, geese, partridges, quail, pheasants, pigeons reared for meat, guinea fowl, ostriches, emus and rheas.
This guide gives you advice on bird-specific diseases, health problems and how to avoid them, and what to do in an outbreak. It covers endemic, notifiable and zoonotic diseases and offers guidance on the relevant poultry health legislation. The guide also provides information on biosecurity measures, the requirement to register birds on the Poultry Register, the Poultry Health Scheme and how to protect workers from health issues particular to the poultry sector.
Keeping poultry healthy and preventing endemic infections
Poultry can be affected by a variety of diseases and parasites, some of which are endemic to certain types of bird. You will need to introduce and maintain a strict hygiene programme to keep diseases out of poultry. As well as carrying out stringent hygiene and biosecurity measures, you will need to carry out vaccination or medication strategies to prevent and/or control certain endemic diseases.
The two most serious diseases that you must keep out of poultry flocks are Newcastle disease and avian influenza (bird flu). Other poultry diseases include chronic respiratory disease, fowl cholera, Salmonella, Campylobacter and internal parasites. Salmonella and Campylobacter, while highly contagious in poultry, are not necessarily life-threatening for fowl. These diseases can however cause serious illness in humans if they get into the food chain.
Daily inspection of poultry by trained staff, in good lighting conditions, and independently of any automatic surveillance equipment, is the best method to prevent serious outbreaks of disease. Inspections will enable you to detect early signs of disease simply by noting changes in the behaviour and condition of individual hens.
The early signs of ill health may include changes in food and water intake, in preening, in ‘chatter’ and in activity. There may also be a drop in egg production and changes in egg quality such as shell defects.
In addition to your own daily, or more frequent, inspections and those of your own veterinarian, membership in the Poultry Health Scheme requires that a mandatory annual inspection and ad hoc inspections be carried out by Animal Health and Veterinary Laboratories Agency (AHVLA) inspectors.
For more information on maintaining good poultry health year-round, see the guide on poultry welfare on the farm and to ensure that poultry reaches market in the best condition, see the guide on poultry welfare off the farm.
Salmonella is a type of bacterium that can cause disease in animals and people. It is one of the most significant causes of food poisoning in humans after Campylobacter. People and animals may become ill if they eat food containing the bacteria or handle infected animals. The illness may be mild or it can be very severe. Some animals and people are infected without being ill at all. They are known as ‘carriers’ and can still spread the disease to others.
Infected animals may produce meat, milk or eggs containing Salmonella. The bacteria may spread to clean food if contaminated produce is not handled hygienically but proper cooking kills Salmonella.
Salmonella is present in the faeces of infected people and animals. Manure from infected livestock can contaminate water. The normal treatment of drinking water supplies removes the bacteria. Vegetable crops may carry Salmonella if untreated water is used for irrigation.
The bacteria live in the intestines of many different sorts of animals as well as in people. Farm animals, pets, horses, birds and reptiles such as tortoises can all be infected. Infection may spread between people, as well as from animals to people.
National Control Programmes (NCPs) for the reduction of Salmonella cover farm animal species which present a potential risk of transmitting Salmonella and other zoonotic agents to humans. These are currently restricted to poultry - ie breeding flocks of Gallus gallus, laying hens, broilers and turkeys.
With regard to poultry, the NCPs affect you if you produce animal feed, engage in primary animal production and/or process and prepare food of animal origin in the following ways:
- set the frequency and percentage for taking samples from flocks
- approve laboratories to which you are permitted to send samples for analysis
- set out control measures if a zoonoses of public health significance is detected
- provide regular assessments of sampling results
- require that you register as a poultry operator
- prescribe the records you must keep on farm
Fowl cholera is a contagious disease of birds. It is caused by a bacterium called Pasteurella multocida and it occurs worldwide. The disease can kill many birds when it first enters a susceptible flock. Recovered birds may become carriers of the bacterium and continue to contaminate the environment.
Older chickens may be more severely affected than young ones and turkeys tend to be more susceptible to infection than chickens. Clinical signs present may include loss of appetite, dullness, diarrhoea and breathlessness. Birds infected for a longer period may have swollen joints.
Parasitic infections and other diseases
Game birds, which are reared in pens before release, tend to be susceptible to parasitic infections, including Hexamitiasis and Trichomoniasis.
A common parasite of significant health and welfare concern is the Red Mite which particularly affects laying hens and can result in significant production loss, as well as down grading of eggs.
Other noteworthy conditions are Coccidiosis, Marek’s disease, infectious bursal disease (Gumboro disease), infectious bronchitis and lameness.
Lead poisoning and exposure can also affect poultry. See the page in this guide on protecting poultry from lead poisoning on farms for further details.
Zoonoses - infections passed from animals to humans
Farm animals can carry a range of diseases, some of which can be passed onto humans. These diseases are known as ‘zoonoses’. Transmission may result from direct contact with a diseased animal, contaminated dung or urine, or through consumption of contaminated farm produce.
Zoonotic infections are monitored in England and Wales through arrangements for both human and animal health. One of the key aspects is the requirement to register all poultry premises with 50 or more birds of mixed species. For more information, see the guide on poultry: an overview.
There are around 40 different zoonoses in the UK and a number of these are classified as notifiable.
To make sure you are carrying out your duty of care, read information relating to Control of Substances Hazardous to Health (COSHH) Regulations 2002 and agricultural workers on the Health & Safety Executive (HSE) website.
Present in a wide range of animals, from poultry to cattle, the E-coli bacteria can survive for many weeks in faeces or soil. Illness following infection may be severe and even fatal, with symptoms including diarrhoea and kidney failure. Infection is caused by eating contaminated food or contact with faeces. Good personal hygiene is essential in prevention of the disease.
Chlamydophila psittaci infection is thought to be common in a number of bird species. It is most common in psittacines such as budgerigars or cockatoos, but also in other species including turkeys, ducks and geese. Infection has also been recorded in people working in pet shops and poultry processing plants.
The psittacosis infection is recognised worldwide. Clinical signs of the disease may only occur when birds are under stress, for example after transport. They include loss of appetite, dullness, laboured breathing, weight loss and diarrhoea.
Minimising health risks on your farm
To reduce the risk to your own health and that of any workers or visitors, you should take a number of precautions. These are highlighted in the relevant HSE information sheet. Download an information sheet on common zoonoses in agriculture from the HSE website (PDF, 84K).
The micro-organisms that cause zoonoses are subject to COSHH. This places a number of obligations on employers and the self-employed to manage the risk, exposure and control by, for example:
- minimising the risk of infection by keeping stock healthy, and vaccinating where appropriate
- ensuring good personal hygiene by washing before eating, drinking or smoking
- wearing overalls when handling animals, especially if they are sick, and gloves and a waterproof apron if handling products of birth or muck and sewage
- washing and covering all cuts and grazes
Common zoonoses include Salmonella and Campylobacter (which cause food poisoning), E-coli (which cause violent diarrhoea) and ringworm (a fungal skin infection). Food poisoning can generally be avoided by ensuring food is prepared and cooked properly, and good hygiene will prevent many other types of zoonoses. Read about Salmonella and Campylobacter on the page in this guide on keeping poultry healthy and preventing endemic infections.
Notifiable diseases: avian influenza
Avian influenza (AI) is a notifiable disease.
Good farming practices are essential to reduce the risk of illness or disease and to prevent them spreading during an outbreak. You should always be vigilant and monitor your stock closely for any early warning signs. For advice on disease prevention relevant to all species of animals, see the guide on disease prevention.
You must report any suspected case of a notifiable disease to your local AHVLA.
The AI virus
There are many strains of AI, which vary in their ability to cause disease.
AI viruses are categorised into two types according to their ability to cause severe disease in species of birds:
- highly pathogenic avian influenza (HPAI)
- low pathogenic avian influenza (LPAI)
LPAI does not always cause obvious disease in birds and is thought to circulate freely within the global wildfowl population.
Some strains of HPAI spread easily and quickly between birds in poultry populations and cause severe disease, with a high death rate. AI is spread by movement of infected birds or contact with respiratory secretions and, in particular, faeces, either directly or through contaminated objects, clothes or vehicles.
Symptoms of HPAI
The effects of HPAI are more noticeable with signs and symptoms that include:
- high mortality rates in flocks
- respiratory distress
- a swollen head
- loss of appetite
- drop in egg production
You should be aware that it is an offence to import, possess or administer AI vaccine without authorisation from Defra. You can read about avian flu vaccination policy and legislation on the Defra website.
Notification and the Great Britain Poultry Register
AI is a notifiable disease, so if you have any suspicion of an outbreak you must notify your local AHVLA immediately. The AHVLA is an executive agency of Defra, responsible for ensuring the welfare of farmed animals - and managing outbreaks of notifiable animal diseases - in Great Britain.
You are also obliged not to move anything off your premises that could spread the disease while you wait for a veterinary inspector to arrive and carry out an investigation. For more information, including how to report a suspected case of AI, see the guide on disease notification and restrictions.
If you have 50 or more birds, you are required to register your premises with the GB Poultry Register. The register enables effective communication with poultry owners at times of heightened risk or actual disease outbreak. If you have fewer than 50 birds, you are also encouraged to register on a voluntary basis. For more information on poultry registration, see the guide on poultry farms: general regulations.
In rare cases, some HPAI strains have led to the infection and death of humans who were in close contact with infected birds. There have also been a limited number of reported cases of person-to-person spread of AI, but no evidence of sustained transmission between people.
A potential future threat to public safety comes from the ability of AI viruses to exchange genetic material with human or other animal influenza viruses. This could create a new virus that humans have little or no immunity to that can spread easily between people.
Defra continually monitors outbreaks of AI around the world, assessing the level of threat each incidence may pose to the UK. Domestically, any suspected cases of AI are investigated, as well as any unusually high mortality events in wild birds, alongside ongoing sampling of both live wild birds and those found dead or killed through hunting.
Notifiable diseases: Newcastle disease
Newcastle disease is a highly contagious bird disease that affects poultry. It is caused by pathogenic strains of Avian Paramyxovirus type 1 (APMV-1). Occasionally virulent strains of Paramyxovirus of pigeon (APMV1) can infect poultry causing Newcastle disease.
Birds affected by this disease include fowls, turkeys, geese, ducks, pheasants, guinea fowl and other wild and captive birds, including ratites such as ostriches.
The clinical signs in affected birds can be variable. The disease can be acute, with sudden onset and high mortality, or mild, with respiratory distress or a drop in egg production as the only detectable signs. A sub-clinical (asymptomatic) form of Newcastle disease and many intermediate forms of the disease can also occur.
Common symptoms include:
- lack of appetite
- respiratory distress - with beak gaping, coughing, sneezing, gurgling and rattling
- yellow/green diarrhoea
- signs of nervousness
- signs of depression
- sudden drop in egg production in laying flocks
- high proportion of eggs laid with abnormally soft shells
Young birds are particularly susceptible and death rates can be high. Survivors often exhibit permanent nervous signs.
Prevention and control
No medical treatment is available for Newcastle disease so the disease can be controlled by:
- isolating outbreaks and culling infected birds
- premises being kept clean and disinfected
- ensuring that carcasses are disposed of properly - see the guide on dealing with animal by-products
- flocks being correctly pest controlled
- avoiding contact with birds of unknown health status
- controlling human traffic on your premises
One age group per farm (‘all in - all out’) breeding is recommended.
Vaccination against Newcastle disease
Virtually all commercial flocks are routinely vaccinated against the disease. There are two types of vaccine available - inactivated vaccines and live vaccines. Inactivated vaccines contain no live virus and are only effective by direct inoculation, which would be impractical on a large scale. Live vaccines can be delivered through spray, aerosolisation, drinking water or direct inoculation and stimulate immune response. This means that they can be delivered to a large number of birds relatively quickly and effectively.
Current vaccines protect birds against clinical disease caused by Newcastle disease, but do not protect against infection. Infected vaccinated birds will excrete the virus, but in relatively small amounts, and will remain apparently healthy.
Newcastle disease is a notifiable disease, so if you have any suspicion of an outbreak you must notify the Department for Environment, Food and Rural Affairs (Defra) immediately. The AHVLA is an executive agency of Defra, responsible for ensuring the welfare of farmed animals - and managing outbreaks of notifiable animal diseases - in Great Britain.
You are also obliged not to move anything off your premises that could spread the disease while you wait for a veterinary inspector to arrive and carry out an investigation. For more information, including how to report a suspected case of Newcastle disease, see the guide on disease notification and restrictions.
Other notifiable diseases related to Newcastle disease
Paramyxovirus of pigeons is caused by a virus belonging to the Newcastle disease group. The clinical signs in pigeons are similar to those seen in Newcastle disease in poultry, including thirst, diarrhoea and the development of nervous signs such as twisting of the neck.
The best protection against the disease is vaccination. Any suspicion of the clinical disease must be notified to the government.
Biosecurity measures for poultry farmers
Owners of animals have a key responsibility in preventing or eradicating disease in animals.
Measures can include careful restocking, practising good biosecurity and being ready to implement measures aimed at controlling specific diseases should they be present.
Biosecurity - meaning ‘safe life’ - is often simply a case of good cleanliness, eg washing hands after handling livestock, or disinfecting boots when visiting markets or other farms.
Practising good biosecurity is particularly important - offering peace of mind, healthy stock and viable businesses.
With a heightened risk of avian influenza (AI) reaching Great Britain, specific advice is offered to keepers of birds in order that this, and other avian diseases, can be prevented or controlled.
Good biosecurity helps prevent the spread of animal disease and plays a vital role in keeping new disease away from animals. It also helps improve farm efficiency and protects neighbouring farms and the countryside.
Key biosecurity measures
- Reduce where possible the movements of people, vehicles or equipment into areas where farm animals are kept. This will minimise potential contamination with manure, slurry and other products that could carry disease.
- Where direct contact with farm animals occurs then cleanse and disinfect protective clothing, footwear, equipment, vehicles before and after contact, or where practicable use disposable protective clothing.
- To avoid disease in a poultry flock it is essential to provide clean drinking water and food, preferably indoors to prevent contamination by wild birds and other animals.
- Other measures include isolating new birds, preparing a plan should the flock need to be brought indoors, and thoroughly cleaning and disinfecting housing at the end of a cycle.
Read more about biosecurity in the guide on disease prevention.
Biosecurity at livestock markets and shows
The spread of disease is a serious risk at livestock markets, where animals come into close contact with other potentially infected livestock or equipment. There are a number of measures that should be taken to minimise this risk:
- do not bring onto or take off the market any vehicle, equipment or clothing contaminated with animal excreta
- do not leave the animal area without cleaning any contamination from your clothes
- do not leave the animal area without cleansing and disinfecting your boots
These rules are enforced under the Animal Gatherings (England) Order 2004.
For more information, see the guide on farmed animal welfare at shows and markets.
Controlled zones during exotic disease outbreaks
When movement and other controls are placed on affected premises during and following an outbreak of avian influenza, Newcastle and other diseases affecting other species, poultry premises may also be subject to movement restraints if they fall within a certain radius of the infected premises, typically to a distance of up to 10 kilometres.
One way by which the disease may spread to domestic birds is through contact with infected wild birds.
To avoid direct or indirect contact with wild birds, particularly waterfowl, you could house birds. Where birds are free range, they should be fed and watered to help avoid contact with wild birds.
In outbreaks of notifiable disease, you may be asked as a statutory requirement to house your birds. Keepers of free-range poultry should have contingency plans to house them in emergencies. For more information on controlled zones and isolating birds, see the guide on disease notification and restrictions.
Worker protection advice
Employers have a legal duty to protect their workers against risks to their health that could arise through work-related activities, and must assess such risks properly. For example, poultry dust, even in healthy flocks, carries its own inherent risks for workers. You can download a leaflet on how to protect poultry workers during deep litter clearing operations from the Health & Safety Executive (HSE) website (PDF, 89K) and download a leaflet on reducing risks when catching poultry from the HSE website (PDF, 64K).
Advice on risk assessments and protecting workers is primarily a matter for the HSE.
Download Defra’s guidance on avoiding the risk of zoonotic infections when working with poultry that is not suspected of having AI from the Agricultural Document Library (ADLib) website (PDF, 1.01MB).
Download Defra’s guidance on avoiding the risk of zoonotic infections when working with poultry that is suspected of having highly pathogenic avian influenza (HPAI) from the ADLib website (PDF, 134K).
Keepers of poultry will wish to be vigilant, to take care if handling birds, which appear to be unwell and to observe high levels of biosecurity.
There are jointly agreed systems for investigating outbreaks of AI in poultry involving Defra, the Department of Health, the Health Protection Agency and the AHVLA. These systems and protocols are designed to ensure that appropriate animal health and public health measures are taken to control disease.
The government has a stockpile of anti-viral drugs, which have been shown to be effective against AI and which would be administered to vets, contractors and workers potentially exposed to HPAI during disease control activities. Seasonal flu vaccination would also be provided.
If you suspect disease, act quickly and consult your vet. Notifiable diseases must be reported to your local divisional veterinary manager.
Other diseases in poultry
In addition to the infections and diseases mentioned in this guide, there are a number of other diseases that you should be aware of as a poultry farmer. The list below is not exhaustive but provides an overview that may be of help to you.
Marek’s disease is a Herpes virus infection of chickens. It can more rarely also be found in turkeys in close association with chickens. The route of infection is usually respiratory and the disease is highly contagious being spread by infective feather-follicle dander, fomites, etc. Infected birds remain viraemic for life. Vertical transmission is not considered to be important.
The clinical signs include paralysis of legs, wings and neck, loss of weight, grey iris or irregular pupil, vision impairment, and raised and roughened skin around feather follicles.
There is no medical treatment available for Marek’s disease. The best way to prevent it is through hygiene, ‘all in - all out’ production, resistant strains, vaccination generally with 1500 PFU of HVT at day old (but increasingly by in-ovo application at transfer), association with other strains (SB1 Sero-type 2) and Rispen’s.
Coccidiosis of turkeys
Coccidiosis is the infection of turkeys with Eimeria spp. Although this disease is not very common in commercially reared turkeys, most turkeys receive preventative medication for at least part of their lives. Five species of Eimeria have been identified that cause lesions in turkeys, of which two are associated with significant disease effects. The virus affects the lower small intestine, rectum and caecae, or the small intestine.
Clinical signs include huddling, weight loss, depression, watery diarrhoea that may occasionally be blood stained or contain clumps of mucus or shed mucosa, tucked appearance and ruffled feathers.
Other birds such as ducks, geese and chicken may also suffer from Coccidiosis.
If you identify this disease in your flock, veterinary treatment is recommended.
Infectious Bursal Disease (IBD) or Gumboro
IBD is a viral disease which targets the bursal component of the immune system of chickens. In addition to the direct economic effects of the clinical disease, the damage caused to the immune system interacts with other pathogens to cause significant effects. The virus is very resistant, persisting for months in houses, faeces etc. Subclinical infection in young chicks results in:
- deficient immunological response to Newcastle disease, Marek’s disease and infectious bronchitis
- susceptibility to inclusion body hepatitis and gangrenous dermatitis
- increased susceptibility to chronic respiratory disease
Clinical signs include depression, inappetance and unsteady gait, huddling under equipment, vent pecking and diarrhoea with urates in mucus.
No specific medical treatment is available. Use of a multivitamin supplement and facilitating access to water may help. Antibiotic medication may be indicated if secondary bacterial infection occurs. IBD can be prevented using a vaccine.
When outbreaks do occur, biosecurity measures may be helpful in limiting the spread between sites, and tracing of contacts may indicate sites on which a more robust vaccination programme is needed.
Protecting poultry from lead poisoning on farms
Lead poisoning can cost you money and kill your poultry. It is illegal for meat and offal from poultry that have accumulated lead above the legal limits to enter the food chain. Lead contamination of eggs from poultry exposed to lead has to be assessed on a case by case basis.
Causes of lead poisoning on farms
Poultry intentionally ingest grit to aid their digestion and as a source of minerals. Typical causes of lead poisoning in poultry are:
- Ingestion of particulate matter in high lead soils.
- Ingestion of lead shot and lead bullets. Clay pigeon shooting has previously been a cause of concern because of the potentially very high levels of lead shot falling onto a limited area of land.
Lead paint is also another source of lead poisoning. Problems have also occurred in broilers and layers due to paint and metallic flakes in recycled sawdust and shavings.
What to do if you suspect lead poisoning
If you suspect some of your farm birds are contaminated with lead, you must:
- consult your veterinary surgeon
- confirm the cause of disease and if lead poisoning is confirmed then identify the source
- remove poultry from the suspected source of lead
Testing for lead in poultry
Advice, post mortem and analytical testing of poultry and eggs for lead is available via your vet and from your regional Veterinary Laboratories Agency (VLA). You can contact the Laboratory Services Department on Tel 01932 357 335.
Poultry Health Scheme
Poultry such as fowl, turkey, guinea fowl, ducks, geese, quails, pigeons, pheasants, partridges and ratites may be traded between any member states. However, animals eligible for intra-European Community trade must comply with harmonised European Union (EU) animal health and welfare rules. You can, however, only export to another EU member state live poultry and hatching eggs from flocks that you have held for more than six weeks in an establishment approved under the scheme.
You must be a member of the Poultry Health Scheme if you wish to:
- export more than 20 birds or hatching eggs to another EU member state
- sell birds or eggs to other Poultry Health Scheme members
- export to certain third countries that require compliance with European Council Directive 90/539/EEC
Membership of the Poultry Health Scheme
Membership of the scheme is open to individuals or companies in Great Britain, operating at specified premises. A member operating with separate premises at more than one location will be required to register each individual premises separately.
The categories of membership of the Poultry Health Scheme are:
- Combined Flock and Hatchery
Membership of the scheme must be approved by Defra - or the Scottish Government or Welsh Government - acting through a local AHVLA Office. A member may withdraw their premises from the scheme at any time, but will not be entitled to a refund of any part of their registration or membership fees.
To join the Poultry Health Scheme you should complete an application form and return it to your local AHVLA Office with a plan of the premises and the registration fee.
Further information and contacting your AHVLA Office
Food Standards Agency Incident Prevention Coordination Team
020 7276 8735
08459 33 55 77