Avian influenza — how to recognise it in your poultry flock?
Sudden mortality, blue combs, collapsed egg production. Highly pathogenic avian influenza (HPAI) moves fast. Learn what to look for and what to do in the first hours of suspicion.
verifiedFrom the team that has organised work on poultry farms for years.
What is HPAI and why do symptoms appear so suddenly?
Highly pathogenic avian influenza (HPAI) is a viral disease caused by H5 and H7 strains. The virus replicates rapidly in the respiratory tract and internal organs, so only 24 to 48 hours may pass between infection and the first deaths. In laying flocks, the first sign is often a dramatic drop in daily egg production — by tens of percent — even before any mortality appears.
Do all avian influenza cases look the same?
No. The severity of signs depends on the virus strain, species and age of the birds, and the immune status of the flock. Waterfowl (ducks, geese) often tolerate infection with milder signs than chickens or turkeys, making early detection harder. Low-pathogenicity avian influenza (LPAI) may run almost without signs or with only mild respiratory problems. However, any suspicion of HPAI requires immediate reporting — differential diagnosis is the veterinarian's responsibility.
Main clinical signs of HPAI in poultry
None of these signs alone proves avian influenza, but their combination — especially the speed and severity — should immediately raise suspicion.
Sudden rise in mortality
Mortality in the flock jumps sharply — from a typical 0.1–0.3% per day to several or even tens of percent within 24 hours. In severe HPAI cases, losses can reach 90–100% of the flock within a few days.
Sharp drop in egg production
In laying and breeder flocks, production can fall by 30–70% or more within 24 to 48 hours. Eggs may be misshapen, thin-shelled, or shell-less.
Apathy and loss of appetite
Birds sit motionless, clustered in corners, unresponsive to stimuli. Feed and water consumption drops visibly — a silo monitor or a daily Flock Card entry in DlaFerm.pl can catch this signal early.
Respiratory signs
Coughing, sneezing, rattling sounds, nasal discharge, open-beak breathing. In ducks and geese, respiratory signs may be the only noticeable symptoms.
Neurological signs
Twisted neck (torticollis), staggering, convulsions, loss of coordination. Neurological signs appear more often in chickens and turkeys than in waterfowl.
Cyanosis and swellings
Cyanosis of the comb, wattles and unfeathered parts of the head — colour shifts from pink to blue-purple. Possible swelling of the head, neck and eyelids. Haemorrhages on the legs and feet.
What to do when avian influenza is suspected?
Time is critical. Every hour of delay increases the risk of the virus spreading to neighbouring farms.
Stop all movement on the farm
Nobody enters or leaves, no birds or biological material leaves the flock. Lock the gate and inform workers.
Call your veterinarian
Your veterinarian is the first point of contact. They will assess the signs and — if suspicion is justified — notify the District Veterinary Officer (PLW).
Report suspicion to the District Veterinary Officer
Farmers are legally required to report HPAI suspicion to the District Veterinary Officer without delay. You can do so by phone — find the number on the GIW website (wetgiw.gov.pl).
Do not dispose of dead birds
Keep dead birds for veterinary examination. Do not remove litter or clean the poultry house — veterinary services will need samples for diagnostics.
Document your observations
Record when you first noticed concerning signs, how many birds have died, and any changes in egg production or feed consumption. The Flock Card in DlaFerm.pl holds a ready daily history.
Differential diagnosis: other diseases with similar signs
Sudden mass mortality can also result from Newcastle disease (ND), infectious bronchitis (IB), Marek's disease, or poisoning. Final differentiation requires laboratory tests — acting on your own is not an option.
Frequently asked questions about avian influenza symptoms
Does avian influenza always cause mass mortality?add
Not always. Low-pathogenicity avian flu (LPAI) can run mildly or without signs. Highly pathogenic strains (HPAI) — particularly H5N1 and H5N8 — typically cause high mortality within days. Waterfowl, however, often show milder signs than chickens or turkeys.
How do I tell avian influenza from Newcastle disease (ND)?add
Both diseases produce similar signs: mortality, collapsed laying, neurological and respiratory symptoms. Clinical differentiation is very difficult and requires laboratory testing (virus isolation, PCR). At any sign of mass mortality or sudden flock collapse, notify a veterinarian immediately.
How quickly must I report HPAI suspicion?add
EU and national law require immediate reporting — without unnecessary delay, in practice as soon as signs are observed. Delay in reporting is a breach of the farmer's obligations and may result in administrative sanctions.
Do I have to cull the flock if I suspect avian influenza?add
The decision to cull (depopulate) the flock belongs solely to the District Veterinary Officer. The farmer cannot make or prevent that decision independently. Until veterinary services arrive, all movement on the farm must stop.
Can I lose compensation if I cull the birds myself?add
Yes. State compensation for lost flocks is only paid when depopulation was ordered by a veterinary authority. If you cull the birds before the District Veterinary Officer's decision, you forfeit the right to compensation.
How does DlaFerm.pl help when HPAI is suspected?add
The Flock Card in DlaFerm.pl records daily mortality, feed consumption and egg production — the first evidence that something was going wrong. The HPAI outbreak map shows active cases near your farm. The QR entry log documents who visited the farm before the suspicion — crucial for the epidemiological investigation.
Sources & resources
- linkGIW — Chief Veterinary Inspectorate Poland: current HPAI information (PL)
- linkEFSA — European Food Safety Authority: avian influenza topic page
- linkPIWet-PIB — National Veterinary Research Institute Pulawy: HPAI diagnostics
- linkDlaFerm.pl — Avian influenza (HPAI): guide for farmers
- linkDlaFerm.pl — Map of active HPAI outbreaks in Poland
- linkDlaFerm.pl — How to report HPAI suspicion
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