Poultry Femoral Head Separation and Necrosis: A Review

Femoral head separation (FHS) is a degenerative skeletal problem in fast-growing poultry wherein the growth plate of the proximal femur separates from its articular cartilage. At its early phase, FHS may remain asymptomatic but lead to epiphyseal breakage, infection, and femoral head necrosis (FHN). Healthy femoral head is viewed as a positive trait for genetic selection. However, the etiology of FHS is poorly understood for use in noninvasive diagnosis and genetic selection. Focal cell death and atrophic changes are likely associated with separation of tissues and necrotic changes. Fibrotic thickening of the articular surface can also impair free movement of the proximal epiphysis in the acetabulum, leading to FHS, under strain. The major limitation to understanding the pathophysiology of FHN is the lack of suitable experimental models and biomarkers to diagnose the problem. In this review, we discuss the possible etiologic factors, anatomic features of the chicken femoral head, biomarkers, and molecular mechanisms relevant to FHN.