Avian influenza (AI) is a highly contagious viral disease that affects both domestic and wild birds. Caused by rapidly evolving viruses grouped into multiple subtypes - such as H5N1, H5N3, and H5N8 – AI continues to circulate globally. While primarily a bird disease, AI viruses have been detected in mammals such as cows, mice, bears or domestic cats (USDA, 2025) including humans (CDC, 2025).

Why Mandatory Housing Happens

When avian influenza risk is high, authorities often mandate the housing of all poultry indoors, including birds normally raised with outdoor access. This is the most widely used preventive measure to reduce contact with wild birds. Across Europe and the UK, ongoing outbreaks of highly pathogenic avian influenza (HPAI) have triggered these precautionary measures. Under EU law (Regulation (EU) 2016/429 and its delegated acts), Member States must confine birds or implement enhanced biosecurity when HPAI risk increases. This means temporary housing rules can suspend outdoor access—even for free-range and organic flocks.

This autumn, 15 of the 27 EU countries have reported bird flu outbreaks on farms (Reuters, 2025). In the UK, the Chief Veterinary Officer announced a mandatory housing order for all of England on 6 November 2025, following escalating cases in kept and wild birds. This came after an Avian Influenza Prevention Zone (AIPZ) was introduced on 30 October 2025 for parts of the UK.

Welfare Concerns During Mandatory Housing

Mandatory housing can pose serious welfare challenges for free range and organic flocks, as many barns are not fully equipped to house the birds for their entire lifecycle. While strict biosecurity is essential to control disease, it’s equally important to adapt housing systems so that birds can still experience good welfare during periods of mandatory confinement.

In France, the National Health Security Agency (ANSES, 2022) reported increased mortality rates in free-range flocks during confinement: up to 6% for flocks housed in summer during a mandatory housing period, compared to 2% for those raised outdoors. Carcass downgrades and condemnations also rose during that period. These issues stem from housing conditions that are not designed for long-term confinement: high stocking densities, poor ventilation, damp litter, and the accumulation of droppings. Together, these conditions can contribute to respiratory issues, locomotion problems, and prevent birds from expressing natural behaviours.

Mitigating Welfare Impacts: Practical Recommendations

To protect welfare during confinement, farmers can adopt these measures:

Regular Monitoring: Regular checks are vital to detect feather pecking, aggression, or illness early. Remove stressed or sick birds promptly. Older birds are particularly vulnerable due to reduced immunity (Soil Association, 2023).
Access to a Winter Garden: A sheltered extension of housing provides natural light, fresh air, and space to encourage natural behaviours while offering the chickens the possibility to choose between indoors and outdoors. It should cover at least 30% of the building’s surface, include clean litter, and offer enrichment like perches and pecking substrates to encourage activity.
Additional Enrichment: It is important to add different types of enrichment and rotate them to maintain interest. Some examples are straw or hay bales, wood shavings, alfalfa blocks, hanging edible objects (e.g., organic cabbages), dust baths with sand or similar substrates.
Reduce Stocking Density: Maximum stocking densities for outdoor systems are normally set considering the birds' use of outdoor areas during the day. During periods of confinement, the birds are housed for extended periods at the densities specified for periods indoors, i.e. at night or in bad weather. The welfare of poultry raised in systems with mobile houses is also particularly affected by periods of confinement. Without access to outdoor areas, stocking densities in these houses can be as high as 17.5 chickens/m², which is not suitable for rustic and active breeds to express their natural behaviours. During confinement, we recommend limiting the stocking density to 25kg/m² to minimise the deterioration of bird welfare. This will give the birds more space to engage in natural behaviours (i.e. foraging, dustbathing, and wing stretching), and is particularly relevant at the end of the production cycle. It also limits litter deterioration, a key factor in maintaining welfare since poor-quality litter promotes feather pecking and other health problems.

Intensive Farming and HPAI Risk

Current biosecurity measures are proving insufficient to fully contain HPAI outbreaks. EFSA stated in 2022 that the emergence of the HPAI A(H5) virus on commercial farms - even when birds are confined indoors - raised concerns about the ability of the applied biosecurity measures to effectively prevent exposure to the virus.

Since biosecurity measures alone cannot stop the disease, the root cause needs to be addressed. Intensive poultry farming fuels repeated, severe disease outbreaks and poses a potential pandemic risk for humans.

Intensive poultry farms, with tens of thousands of genetically similar birds in crowded, stressful conditions, create ideal environments for viruses to spread and mutate into highly pathogenic strains. These systems provide a constant supply of new hosts, accelerating viral evolution, and increasing the risk of the virus reaching wild birds and mammals.

In response to the ongoing AI outbreak risks, a systemic reform of the poultry sector is needed. Without it, bird flu will continue to devastate animal populations and pose risks to human health. Key recommendations include reducing stocking densities, limiting flock sizes, ending the clustering of farms in high-density regions, and breeding more robust and, more importantly, genetically diverse birds with greater natural immunity.

To truly safeguard animal welfare, public health and food security, governments and industry must move beyond short-term fixes. Integrated strategies that tackle the root causes of Avian Influenza are essential, rather than relying solely on biosecurity measures, temporary confinement of free-range flocks, and emergency on-farm mass culling of birds. Industry must lead the way by prioritising sustainable farming systems and introducing standards that reduce overcrowding and stress in poultry production.

References

Anses (2022) AVIS de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif aux « conditions de mise à l’abri des volailles élevées en plein air en vue de la prévention de l’introduction de virus influenza aviaires hautement pathogènes par des oiseaux sauvages

CDC (2025) Global Summary of Recent Human Cases of H5N1 Bird Flu

CIWF (2023) Bird flu: Only major farm reforms can end it

EFSA (European Food Safety Authority), 2022. Scientific report: Avian influenza overview May – September 2021. EFSA Journal 2022; 20(1):7122, 76 pp. doi:10.2903/j.efsa.2022.7122 (7

Reuters (2025) Europe races to lock down poultry as bird flu takes hold

Soil Association (2023) Avian Influenza: Guidance on coping with housing orders & maintaining good flock welfare

Avian Influenza: Impact, Regulations, and Welfare Challenges