Early poultry selection programs for feed efficiency and production traits alone have been proven successful at developing commercial lines of highly prolific layers and fast-growing broilers. Yet, such genetic potential for only desirable production traits often falls below actual on-farm flock performance since commercial conditions can be stressful and challenging, potentially taking a toll on birds’ physical and mental health.
Pushing toward resilience
Further improvements in feed efficiency, from nutrient intake to utilization, are still a must nowadays because of the never-ending worldwide pressure to optimize resource utilization for sustainable production. And, to attain such desirable production outcomes, birds need to stay healthy (physically and mentally) until the end of their production cycle. Although some producers can already get closer to performance objectives described by breeding companies, the reality for most of them is quite different for different reasons. Firstly, commercial conditions can be undoubtedly challenging and stressful for birds and each production system faces its own struggles. For example, cage systems for laying hens offer limited opportunities to engage in species-specific behaviours and physical exercise which can result in feather pecking problems while managing birds in multitier systems require efforts to prevent bone fractures and deviations. Secondly, and generally speaking, managing barns housing large volumes of birds at high stocking densities can become a struggle from a biosecurity standpoint as preventing disease spread and containing outbreaks is tough. Thirdly, breeding facilities where pedigree and grandparent lines are housed poorly reflect housing conditions in commercial barns due to high biosecurity protocols and standards in place, high-tech facilities, specialized management to phenotype performance throughout lifetime, and relatively small flock size. All of these create a mismatch between expected objectives vs observed performance under commercial conditions. Then, the closer commercial conditions resemble those in breeding facilities, the lower the gap between the actual flock performance on-farm and the target.
The stressful nature of commercial conditions is unavoidable, just like the potential biosecurity risks of disease outbreak or pathogen exposure. So, birds must be competent at coping successfully with potential stressors and biological agents which can threaten their (physical and mental) well-being and performance. This ability to remain steady and unaffected by external threats is so-called resilience, and selecting for this trait can benefit producers that struggle at keeping indoor conditions well-balanced in terms of within comfort zone, stress-free, and secure from physical and biological hazards. When it comes to body’s defenses against diseases, birds must develop a competent, immune response to perform well under commercial conditions, particularly if there is room to improve barn cleanliness standards. Including such immunological traits in their breeding schemes can help develop more resilient poultry lines to local conditions and lower the severity of biosecurity breaches. Similarly, including stress markers into breeding programs (i.e., number of fault bars in feathers) can help identify how birds cope with environmental stress and select those with proven coping skills. Thus, adding metrics related to how well birds can cope with commercial conditions in breeding selection schemes, on top of performance and health outcomes, can help develop more resilient poultry breeds and tackle current gap between genetic potential and on-farm performance.
Seeking adaptability
The globalization of the poultry sector might drive the mindset that one chicken breed can be employed in any production system across countries and achieve optimal performance in all of them, which is far from reality. On the other side, thinking about how well adapted poultry breeds are to conventional production systems can benefit the poultry industry become more sustainable. In this context, the genotype-environment interaction gains weight either 1) adjusting poultry houses and management to the needs of highly prolific breeds or 2) selecting the most productive birds that suit the best to local conditions and production system (e.g., aviaries or furnished cages). This perspective can allow producers to choose the genetic background that fits nicely to their needs and reach reliable performance outcomes. Also, from a welfare standpoint, this approach can mitigate the number of losses and birds left behind by the end of the production cycle due to enhanced fitness and competitiveness of each bird. Tunning this interaction between genotype and environment also enables breeding companies to cover a wide range of market needs and niches, from modern breeds to more traditional and heritage lines, and deliver specific solutions to producers’ needs. Similarly, and beside making commercially available this genetic variability, producers must also be aware of what birds suit the best to their management and care instead of seeking highly prolific lines since they can achieve overall greater revenue choosing the right bird for them.
Research in this field has noted that poultry breeds respond differently to husbandry systems but also to flock management. For example, management practices such as easing early feeding and hatchery-to-brooder transition, mitigating lifetime distress, maintaining a healthy body conformation uniformly, photo-stimulating at the right time, and upholding solid biosecurity standards are key determinants to achieve full genetic potential of highly prolific lines. However, putting this knowledge consistently into practice daily is demanding, and for producers who may struggle with this, alternative easy-going and resilient breeds can be a better fit for them to attain greater performance and well-being.
