Avian Influenza and Free-range Hens in Spain: Impact of Confinement and Technical Strategies to Mitigate Stress and Its Consequences

Introduction

The recent reactivation of avian influenza episodes in Europe, particularly in Spain, has forced authorities to ramp up surveillance and prevention measures. The Ministry of Agriculture, Fisheries, and Food (MAPA) has decreed the confinement of poultry reared outdoors—including all free-range and organic farms—to prevent contact between domestic poultry and potentially high-pathogenic virus-carrying migratory wild species.

These measures, necessary for sanitary reasons, have direct consequences on animal welfare, production, and the sector’s economy.

We will analyze the epidemiological situation, official measures, economic impact, and, in a practical and technical way, strategies to minimize stress in confined hens, with special attention to the use of rehydration agents and anti-pecking cubes or devices.

Current Epidemiological Situation in Spain

In recent months, Spain has suffered a significant escalation in Highly Pathogenic Avian Influenza (HPAI) outbreaks, prompting urgent measures such as confining free-range poultry to avoid contact with wild birds. According to MAPA’s latest data, 14 outbreaks have been identified in professional poultry farms, with approximately 2.5 million hens culled to date. These numbers affect farms in several regions (Castilla y León, Castilla-La Mancha, Andalusia, Extremadura, and Madrid) and include both egg-laying and other types of farms. From the start of the season (July 1, 2025) to early November, 139 outbreaks have been detected in poultry across the European Union, placing Spain at risk when evaluating the virus’s continental circulation.

Key Epidemiological Points:

• Virus varieties: Predominance of H5 subtypes (H5N1 and other H5 lineages) associated with high pathogenicity in birds; these subtypes show genetic variability requiring constant monitoring.

• Entry pathways: Migratory waterfowl, indirect contact through contaminated water and feed, vehicles, personnel, and equipment, which can act as vectors.

• Environmental persistence: Low temperatures increase the virus’s stability in water and substrates, raising the risk of indirect transmission.

Measures Adopted by MAPA and Their Technical Basis

MAPA has issued orders and technical notes that include, among other measures, the confinement of outdoor-reared poultry, the protection of water tanks from wild birds, a ban on supplying water from tanks accessible to wild birds unless treated to inactivate the virus, and reinforcement of biosecurity (access controls, cleaning and disinfection, movement recording). These actions are based on reducing three critical risk factors: exposure, indirect contact, and intra-operation amplification, in line with government directives.

• Physical confinement: Prevent outdoor access via mesh or keeping birds inside barns.

• Water and feeding: Prevent wild birds from accessing tanks; if at risk, treat or chlorinate water to levels that inactivate the virus and ensure frequent cleaning of feeders and drinkers.

• Surveillance and notification: More frequent health checks, sampling on farms with unusual mortalities, and movement restrictions in affected areas.

Expected Economic and Productive Impact

The economic impact is multifactorial and can be divided into direct and indirect effects:

1. Direct effects on production

   • Reduced laying rates and decreased quality (spots, changes in shell morphology, altered fat/water content) linked to stress from management changes and restricted natural behavior.

   • Increased mortality and possible culling at farms with confirmed outbreaks—recent outbreaks have seen mass culling, causing significant direct losses, a special risk for all poultry.

2. Effects from management and sanitary measures

   • Additional costs for biosecurity (netting, tank protection systems, disinfection equipment, labor).

   • Losses due to reduced feed efficiency and the need for treatments or palliative measures (supplementation, rehydration, behavioral corrections).

3. Market and commercial effects

   • Export restrictions and demand changes; market closures and import bans by third countries can reduce prices and sales volume.

   • Potential loss of the distinguishing value of “free-range” or “organic” eggs if consumers perceive any changes in quality or production conditions, although authorities are allowing commercial codes (0 and 1) to be maintained if regulations are met.

Altogether, these factors could significantly reduce profitability during the restriction period, especially if confinement is prolonged. Concrete estimates vary by region, production density, and duration, so each farm needs an adapted economic and health plan.

Effects of Confinement on Welfare

Free-range hens exhibit specific motor and social behaviors (foraging, scratching, nesting, exercise) which are limited by confinement. Sudden closure from the outside is an acute stressor and, if prolonged, may become a chronic one, with the following critical effects:

• Neuroendocrine response: increased hypothalamus–pituitary–adrenal axis activity (cortisol/corticosterone) alters metabolism (reduced intake, mobilization of reserves, effects on ovulation and egg quality).

• Abnormal behaviors: increased pecking and cannibalism due to frustration and sensory overstimulation; reduced resource access and changes in social hierarchy heighten aggression.

• Digestive health: Stress may alter intestinal motility, microbiota, and predispose to imbalances that affect feed conversion and eggshell quality.

• Immunocompetence: Immune responses may be depressed by chronic stress, increasing susceptibility to opportunistic pathogens.

Intervention should not only focus on virus prevention but on management strategies to minimize stress and its productive consequences.

Practical Strategies to Reduce Stress During Confinement

Here are practical measures—based on welfare, management, and nutrition principles—that can be quickly and effectively implemented on free-range farms that must remain closed.

1. Physical Environment and Enrichment

   • Space reorganization: Increase availability of perches, scratching areas, and indoor platforms to offer vertical gradients and promote movement.

   • Manipulable enrichment: Introduce objects that foster exploration (hampers, ropes, blocks) and distribute attention.

   • Light and noise control: Maintain stable light cycles and avoid abrupt changes; reduce external noises that increase stress.

2. Group Management and Density

   • Avoid overcrowding: If possible, reduce density per surface area to minimize conflicts.

   • Social hierarchy management: Observe groups and segregate highly aggressive or pecked birds to stop the imitation chain.

   • Temporary separation and gradual reintroduction: For established pecking outbreaks, temporary relocation and a gradual reintroduction program with enrichment may be needed.

3. Nutritional Interventions: Rehydration and Complementary Feeds

In confinement, nutritional and health management should aim to maintain the hens’ physiological stability and reduce stress impact.

One of the most effective tools at the start is Bilantul Rehidra by AMBiotec, a rehydrant specifically formulated to quickly restore water and electrolyte balance.

Its formula, based on mineral salts, rapidly available energy, and pH regulators, helps restore intake and maintain acid–base balance when hens typically reduce intake due to a sudden change in environment. Administering it via drinkers for the first 48–72 hours helps ensure a smoother transition to new management conditions and minimizes the risk of dehydration or production drop due to initial stress.

Alongside hydration, digestive integrity is critical as ongoing stress can alter the microbiota, intestinal motility, and absorption of nutrients essential for laying. Here CocciCero stands out as a strategic tool, acting on subclinical coccidia pressure, very common when the immune system is compromised, and improving gut functionality. This results in higher feed efficiency and more stable delivery of minerals and nutrients involved in egg formation.

This combined action keeps hens in an ecologically suitable state during confinement, yielding more consistent egg quality and reducing shell defects or internal variations typically seen with prolonged stress.

4. Specific Anti-pecking Measures: Cubes and Anti-pecking Devices

Pecking is the most concerning behavioral consequence of confinement. Strategies should integrate environmental, nutritional, and physical aspects.

Anti-pecking nutritional cubes act as focused enrichment, redirecting attention towards safe, prolonged manipulative activity.

Rich in technical fibers, textures promoting natural beak wear, and aromatic attractants, they encourage exploration and reduce the likelihood of hens pecking each other. Distributing several cubes around the barn reduces competition and helps stabilize group behavior, preventing injuries, feather loss, and productivity drops due to social stress.

Other anti-pecking solutions:

• Beak tip covers (e.g., plastic “nails”) and physical modifications (nets) can be drastic and require welfare and legal evaluation.

• Visual correctors (light markings, hanging objects) and distributing food in multiple feeders reduce aggression focus.

Implementation Protocols: Practical Step-by-step Proposal

• Day 0 (start of confinement)

  • Implement reinforced biosecurity: entry control, cleaning, disinfection.

  • Check water tanks and adapt protection; activate treatment if necessary.

  • Install anti-pecking cubes proportionally to density (e.g., 1 unit/100 birds as a starting point).

  • Prepare rehydrant solution and plan administration through drinkers.

• Days 1–3

  • Provide rehydrants for 24–72 h depending on intake; monitor water and feed consumption.

  • Increase enrichment (perches, hanging objects) and maintain stable lighting cycles.

  • Identify aggressive birds and start segregation if required.

• Days 4–7

  • Evaluate pecking appearance: if it persists, increase the number of cubes and stimulus rotation.

  • Consider phytobiotic supplementation if signs of chronic stress appear.

• Days 8–14

  • Reevaluate production indicators (laying rates, egg quality, consumption).

  • Adjust density/resources and continue health monitoring.

  • Prepare an outdoor-return plan (if applicable) with gradual reintroduction and measures for wild bird protection.

Measuring Success: Indicators to Monitor

To assess the effectiveness of measures, record quantifiable indicators:

• Water and feed consumption.

• Number of daily lays and egg quality (weight, shell defects).

• Pecking incidence (new cases/day) and number of birds treated/segregated.

• Daily mortality and causes.

• Welfare parameters (behavioral observations, activity index).

Daily records and data-driven decision-making allow interventions to be adjusted and losses minimized.

Conclusions and Final Recommendations

1. Risk–benefit balance: The confinement ordered by MAPA is a justified health measure to reduce the risk of HPAI introduction and spread. However, its impact on welfare and production requires prompt, coordinated countermeasures.

2. Integrated action: Combining strict biosecurity, environmental enrichment, density management, nutritional interventions (rehydrants and phytobiotics), and anti-pecking devices offers the best strategy to minimize productive losses and animal suffering.

3. Record and adapt: Monitoring productive and behavioral indicators allows real-time adaptation and justifies decisions to auditors and authorities.

4. Economic preparation: Planning for extra costs and seeking support (subsidies, insurance, regional measures) can reduce the financial impact, especially for small and medium-sized operations.

Frequently Asked Questions (FAQ)

1. Why has the confinement of free-range hens in Spain been decreed?

Confinement is a preventive measure adopted by MAPA to avoid contact between all virus-carrying birds (domestic and wild) of avian influenza. This decision reduces the risk of virus introduction and spread, especially during periods of high epidemiological circulation associated with migratory birds.

2. Does this confinement affect the commercial classification of free-range eggs?

Although hens cannot temporarily access the outdoors, the regulations allow their classification to be maintained as long as specific requirements are met and the confinement is the direct result of a health order. Still, it is advisable to communicate the exceptional reason to clients to avoid confusion about contagion risks.

3. What productive consequences may arise during confinement?

The most common effects are reduced lay rates, decreased egg quality (more defective eggs), changes in social hierarchy, increased pecking, and decreased feed and water intake in the first days. These are mainly due to stress from limited natural behavior and abrupt management changes.

4. How does Bilantul Rehidra help during the first days of confinement?

Bilantul Rehidra helps restore intake, stabilizes electrolyte balance, and maintains acid–base homeostasis at a key moment. By providing quickly available electrolytes and energy, it reduces the acute stress impact, preventing dehydration and improving the hens’ initial adaptation to confinement.

5. Why is it important to reinforce digestive health during this period?

Stress affects the microbiota, decreases nutrient absorption, and compromises gut function, impacting feed efficiency and egg quality. Maintaining a stable digestive tract is essential to sustain production and avoid economic losses throughout the restriction period.

6. What role does Cocci Cero play during confinement?

Cocci Cero acts against subclinical coccidia pressure, more common when the immune system is stressed. It also improves intestinal integrity, promoting more efficient absorption of nutrients and minerals, helping maintain more consistent egg quality and reducing shell defects.

7. How do anti-pecking nutritional cubes help control aggressive behaviors?

These cubes provide a manipulative stimulus that keeps hens busy, reduces anxiety, and distracts attention from pecking behaviors directed at other birds. Their formulation—rich in fibers, textures, and aromatic attractants—prolongs interaction and helps stabilize social hierarchy, reducing injuries and productivity losses.

8. Can pecking be completely avoided during confinement?

It can be significantly reduced, but not entirely eliminated, as it depends on genetics, density, flock history, environmental quality, and previous stress levels. The key is to combine environmental enrichment, adequate hydration, digestive support, and continuous monitoring.

9. How long do hens take to adapt to the new management?

They generally need 5 to 10 days to stabilize their behavior and recover productive normality, though this can vary by flock condition, quality of the indoor environment, and how quickly support measures are implemented.

10. What indicators should be monitored to evaluate if interventions are working?

It’s vital to track water and feed intake, daily lay numbers, egg quality, pecking incidence, mortality, and any behavioral changes. These indicators enable early intervention adjustments and help avoid small issues becoming costly losses.

11. Can confinement cause immune problems?

Yes. Prolonged stress can reduce immune capacity, increasing susceptibility to digestive and respiratory diseases. Maintaining gut integrity and ensuring optimal hydration are critical, as both directly affect immune response.

12. When can anti-pecking cubes be withdrawn and intensive measures reduced?

When the flock has stabilized behaviorally, pecking is under control, productive parameters have normalized, and the health authority lifts the confinement order. However, it’s recommended to maintain minimum enrichment to avoid relapses.