Avian influenza (highly pathogenic avian influenza, HPAI, ‘bird flu’) and the requirement to keep poultry indoors
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 flocks consisting solely of geese 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 geese then feed and drink from the same places, they can become infected with the virus. Geese must therefore only be fed outdoors in areas that are inaccessible to wild birds, and must not be watered from surface water to which wild birds have access (Section 3 GPVO).
The pathogen, which is excreted by infected animals in their droppings as well as in secretions from the nose and eyes, can also find its way into the barn via contaminated footwear or clothing. Hygiene chambers at the barn entrances, where clothing and footwear are changed and hands are washed before entering the barn, 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 pathogen. 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.
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).
However, if geese accustomed to grazing must be kept indoors for animal health reasons, the following animal welfare issues are to be expected:
- Refusal to eat or drink for several days, apathy
- Crowding together (crushing)
- Occurrence of feather pecking and cannibalism
- Stress-induced moulting
- Increased susceptibility to disease
- Increased mortality
- Increased stress for the birds due to more frequent human contact during daily care tasks in the barn
- Care tasks in the house (e.g. bedding).
Therefore, an exemption should be applied for from the competent veterinary authority in accordance with Section 13(3) of the Avian Influenza Ordinance. To mitigate the aforementioned problems, anyone who is able to do so should move the animals into a barn or similar facility at night so that they can become accustomed to it.
Irrespective of this, every animal keeper should have an individual ‘animal disease contingency plan’ in place, setting out the measures to be taken in the event of a compulsory housing order and how the requirements of Section 13(3) sentence 1 no. 2 of the Avian Influenza Ordinance can be met in the event of an exemption being granted. Further information on drawing up an individual animal disease contingency plan can be found in Annex 5 of the Goose Husbandry Agreement.
The housing orders issued during recent outbreaks of avian influenza repeatedly confirm the high levels of stress experienced by the animals when they are required to remain indoors. In the event of a housing order, far-reaching measures such as more frequent checks on the animals and the provision of additional enrichment materials (e.g. fresh straw or maize silage), alongside sufficient space, are therefore of the utmost importance.