POSTHATCH DEVELOPMENT IN POULTRY

This article reviews the gross and microscopic changes occurring in th e gastrointestinal tract of newly hatched birds in conjunction with ch anges occurring in enzyme activity and biliary secretion to the duoden um. Together, these processes influence digestion and absorption of ex ogenous feed. Enhanced growth found in larger birds at hatching becaus e of early availability of nutrients is described. Manipulation to the nutrient supply after hatch has both immediate and delayed effects on growth and feed utilization and some of these changes can be explaine d by differing patterns of developmental changes.