Avian influenza is a fatal disease affecting birds. Chickens and turkeys are particularly severely affected, whilst geese and ducks exhibit milder symptoms.

The control of avian influenza is regulated by applicable EU law and, in Germany, additionally by the Avian Influenza Ordinance (GPVO). Among other things, the Ordinance stipulates that if mortality rates exceed 2% within 24 hours, or if there is a significant increase in animal losses in pure duck flocks over a period of more than four days, avian influenza must be ruled out as the cause by a vet (Section 4 GPVO).

To prevent the spread of the virus and to prevent it from entering one’s own flock, it is important to understand the routes of transmission and to take appropriate precautionary measures.

One of the most important measures is to prevent contact between farmed poultry and wild birds and their droppings. Open water bodies and feed provided in outdoor runs, for example, can attract infected wild birds. If the ducks then feed and drink from the same places, they can become infected with the virus. Poultry must therefore only be fed outdoors in areas inaccessible to wild birds and must not be watered using surface water to which wild birds have access (Section 3 GPVO).

The pathogen, which is excreted by infected animals in their faeces as well as in secretions from the nose and eyes, can find its way into the shed via contaminated footwear or clothing. Hygiene chambers at the shed entrances, where clothing and footwear are changed and hands are washed before entering the shed, play a significant role in reducing the risk of introduction. Vehicles that drive across the farmyard or even into the barn, such as the litter spreader, pose a high risk of introducing the virus. Therefore, forecourts and paths should be paved and, like the vehicles, cleaned regularly and disinfected where necessary.

Feed or the straw bedding itself can also lead to the unintended introduction of the virus into the barn if these are not stored safely away from wild birds. The GPVO therefore stipulates that feed, bedding and other items with which poultry may come into contact must be stored in a manner inaccessible to wild birds (Section 6(3) GPVO).

Straw or bedding must be stored at least under cover; ideally, it should be stored in enclosed premises. Straw that must be stored outdoors must be covered with a sturdy plastic sheet and/or a net (see Figure 23).

In particular, the risk of HPAI introduction is higher in free-range systems compared to purely indoor housing systems, and appropriate precautionary measures must be taken. If the competent authority assesses the risk of HPAI occurrence as high, a mandatory housing order may therefore be issued (Section 13(1) GPVO).