Among the major contributors to global poultry meat and egg production, European (EU) countries play a significant role in setting high standards for quality and animal welfare, serving as both a major producer and supplier to international markets (1). Achieving high levels of production is the result of a combination of production policies, market regulations, integrated health and production management strategies. Biosecurity is widely recognized as a key tool for preventing the introduction of infectious diseases (external biosecurity) and the establishment and spread (internal biosecurity) from and within an animal production site, which in turn reduces antimicrobial usage and enhances animal production performance (2–4). Although all EU member states are subject to the same overarching legal framework for animal health (5), the practical implementation of biosecurity measures can vary significantly across countries (2, 6–8). These differences reflect the diverse needs of national poultry sectors and are expressed through tailor-made national biosecurity legislation (9) and/or country-specific quality label regulations (10, 11). The implementation of biosecurity measures also depends on various country-specific factors, such as geographical location of farms, their structural characteristics (e.g., size, production type, and category), the national epidemiological situation (e.g., presence, prevalence, or risk profile of poultry diseases), available financial resources, and the awareness and knowledge of stakeholders regarding biosecurity (12–14). A further challenge is the scarcity of available data on the actual level of biosecurity implementation in poultry farms across European countries (15–17). This data gap represents a bottleneck for the design of effective interventions aimed at improving biosecurity implementation (9, 12, 18). In response to these knowledge gaps, the COST Action CA20103 - Biosecurity Enhanced Through Training Evaluation and Raising Awareness (BETTER) - was launched in 2021. One of its aims is to gather and consolidate knowledge on biosecurity regulatory frameworks.¹ To this end, an overview of biosecurity implementation as mandated by national legislation and other regulatory frameworks in intensive poultry production was performed (8). The analysis revealed a general lack of data on the actual level of implementation of biosecurity measures in most countries. Therefore, a comprehensive and systematic assessment was needed to address this important gap. The objective of this study was to assess the level of biosecurity implementation in poultry farms across key European countries contributing to the global poultry market. In addition to European COST member countries, Turkey (Full COST Member), Tunisia (Near Neighbor Country), and Israel (Cooperating Member), were also included in the analysis.

This systematic review was conducted in accordance with the Cochrane Handbook for Systematic Reviews (19) and is reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (20).

This systematic review provides an overview of the level of biosecurity implementation in poultry farms across Europe and neighboring regions. Despite continuous research efforts over the past two decades (2003–2023), our findings reveal considerable variability in the implementation of biosecurity practices. This heterogeneity, driven by a wide range of study designs, poultry species, and methodological approaches, highlights the complexity of evaluating biosecurity across diverse national contexts.

This review also highlights the variability in methods used to assess biosecurity, namely descriptive analyses (e.g., reporting the percentage or the number of farms implementing specific measures), scoring systems (e.g., self-scores, Biocheck. Ugent™, national scoring systems, FAO’s Zone Biosecurity model) and probabilistic/simulation models. Similar results have recently been reported by Duarte et al. (25), who identified 33 different methods used to assess biosecurity in poultry farms in Europe and beyond. Descriptive approaches were the most common among the articles analyzed in our study. While such methods provide useful baseline data, the absence of standardized lists and definitions of biosecurity measures poses a challenge for generating comparable outputs across countries (26). In contrast, 13 studies employed scoring systems. Among these, Biocheck. UGent™⁵ was the most commonly used tool, enabling standardized and reproducible assessments of farm biosecurity (27). Probabilistic models (used in 10 studies) also offer valuable insights into the likelihood of pathogen introduction and spread under specific farm conditions (28). However, these models often rely on simulated data rather than empirical on-farm assessments (29). The integration of scoring systems with probabilistic modeling could serve as a standardized and powerful tool for national and regional surveillance, benchmarking, and supporting farm-level decision-making. By combining both systems, a comprehensive approach to data collection and analysis could help identify emerging trends and high-risk areas, thereby reinforcing national and regional surveillance programs. At the farm level, predictive models based on real-world data can support evidence-based decisions, such as optimizing vaccination timing against diseases or intensifying biosecurity measures during high-risk periods (e.g., for avian influenza introduction from wild birds).

Based on descriptive data from 1,692 farms, 58% of farms implemented all the biosecurity measures assessed. In addition, external and internal biosecurity measures were implemented by 57 and 60% of farmers, respectively. However, these values may not fully reflect the actual level of biosecurity implementation, as many studies using descriptive methods assessed the presence of a measure rather than its correct application. For example, in García-Sánchez et al. (30), the question “Does the farm have a vehicle wheel disinfection system?” did not assess whether the system was actually used. Future studies using descriptive methods should include tools that verify whether the measure, when present, is also implemented correctly (31). From the scoring evaluation, the overall average biosecurity score was 66.9/100 with external and internal biosecurity scoring 68.0/100 and 65.8/100, respectively. The majority of these studies focused on broiler farms, highlighting the efforts of EU countries over the last decade to strengthen biosecurity in poultry production. Regulatory frameworks, including Regulation (EU) 2016/429 and related national policies (32), have further supported implementation. Additionally, this likely reflects the economic relevance and industrial standardization of broiler production (33), but also the ease of data collection linked to their shorter production cycles.

Notable differences emerged across specific biosecurity subcategories. Measures related to cleaning and disinfection and the purchase of one-day-old chicks were most commonly implemented in studies using descriptive methods. In contrast, infrastructure and biological vectors, and disease management scored highest in studies using scoring systems. This divergence may be linked to differences in evaluation principles: descriptive evaluations do not assign weights, whereas scoring systems apply risk-based weightings (34).

Most studies (34 out of 44) were pathogen- or disease-specific (e.g., Campylobacter spp., Salmonella spp., and avian influenza), while only 10 studies focused on evaluating biosecurity measures. This suggests that biosecurity is still perceived as a reactive intervention within epidemiological frameworks rather than a proactive management strategy (30, 35, 36). A shift toward a more holistic and integrative approach, capable of preventing multiple hazards, would foster more resilient poultry health systems.

A majority of studies (77%) focused on a single poultry species, primarily broilers (55%), while assessments involving layers or turkeys were far less frequent. Although this review included solely primary research studies, this imbalance reveals a gap in biosecurity assessments for other systems (e.g., extensive or organic poultry farming, turkeys, and minor poultry species), which may also pose potential zoonotic risks (37).

Some studies (23%) evaluated multiple poultry categories, offering broader insights but often without disaggregated results by production type. Almost all such studies (7 out 10) were conducted during disease outbreaks (especially avian influenza) involving multiple poultry types in a region. For example, Knight-Jones et al. (38) administered a questionnaire during an avian influenza outbreak to holdings within 10 km of infected premises, regardless of species. In Sweden, biosecurity data were collected during a major avian influenza outbreak affecting over 2.2 million birds (39). While these studies offer comprehensive overviews, they often lack production-type–specific detail. Given that avian influenza affects various poultry species, future outbreak-based studies should enable comparisons between broilers, layers, and turkeys. Ssematimba et al. (40), for example, conducted detailed interviews with 42 farmers and 18 poultry business representatives during the H7N7 epidemic in the Netherlands. Their sample was adjusted to represent the national poultry population, allowing insights into biosecurity variation across production types. Future research should therefore combine species-specific and cross-cutting approaches when evaluating biosecurity protocols.

Despite broad geographical coverage—including eight multi-country studies with 36 national assessments—the distribution of studies remains uneven. Countries such as the United Kingdom, France, and the Netherlands are well represented, while others (e.g., Cyprus, Finland, Greece, Ireland, Kosovo, Serbia, Sweden, Tunisia, and Turkey) are covered by only a single study. This imbalance may reflect differences in research funding, national priorities, or logistical barriers to conducting longitudinal studies, or differences in the impact of national poultry production at European level.

Most reviewed studies targeted conventional systems (73%), while few addressed organic or free-range production systems. Given the growing demand for products from systems perceived to offer higher welfare (41), future studies should investigate biosecurity in these contexts. Expanding research into non-conventional systems would help fill critical knowledge gaps and support policy development.

This study aimed to systematically review the level of biosecurity implementation in poultry farms across Europe and neighboring countries. The findings indicate that biosecurity implementation is highly variable, with notable differences in both geographical coverage and the types of poultry systems assessed. Several key areas for improvement emerged from this review, including: (i) the need for more published data on layers, turkeys, and other poultry types beyond broilers, to develop a more comprehensive understanding of biosecurity across diverse systems; (ii) the promotion of cross-country collaboration, capacity building, and targeted resource allocation to enhance research output, data harmonization, and knowledge sharing; and (iii) increased research on alternative (e.g., extensive and organic) poultry production systems, to better understand how production models influence biosecurity implementation and effectiveness.

Addressing these gaps will strengthen future efforts to implement and monitor biosecurity measures, ultimately reducing disease transmission risks and supporting a safer, more resilient poultry sector.