Sternal Region in Poultry: Linking Skeletal and Muscular Disorders Associated with Keel Bone Damage in Laying Hens and Breast Muscle Myopathies in Broilers

Poultry production is one of the most intensive sectors of animal production providing a significant source of animal protein through meat and eggs. However, increasing production intensity has brought challenges related to animal health, welfare, and product quality. In chickens (Gallus gallus domesticus), the sterno-pectoral region represents a key anatomical and functional unit that supports the birds’ body and is essential for locomotion and respiration. This region is particularly susceptible to the adverse effects of intensive selection and production in both broilers, i.e., meat production, and laying hens, i.e., egg production. Skeletal disorders of the sternum, predominantly observed in laying hens, and breast muscle myopathies, primarily affecting broilers, are typically investigated as separate conditions. However, their anatomical co-localization, shared developmental background, and common risk factors suggest they should be considered within a unified framework. The aim of this review is to integrate the current knowledge on skeletal and muscular disorders of the sterno-pectoral region, with emphasis on their interrelationships, underlying mechanisms, and implications for production efficiency and animal welfare. By identifying this region as a critical hotspot for production-related pathology, this review offers a more comprehensive perspective on the biological limits of intensive poultry production and highlights the importance of an integrated approach as the foundation for developing future breeding and production strategies.