Posthatch Development in Poultry

Abstract

This article reviews the gross and microscopic changes occurring in the gastro-intestinal tract of newly hatched birds in conjunction with changes occurring in enzyme activity and biliary secretion to the duodenum. Together, these processes influence digestion and absorption of exogenous feed. Enhanced growth found in larger birds at hatching because of early availability of nutrients is described. Manipulation of the nutrient supply after hatch has both immediate and delayed effects on growth and feed utilization and some of these changes can be explained by differing patterns of developmental changes.