Body Weight Uniformity and Eggshell Quality of Hens in a Free Range Production System

Abstract

Birds from seven flocks of commercial free-range hens were weighed at the ages of 19, 26, 37, 50 and 60 weeks. Body weight increased with increasing hen age for all flocks. Flock uniformity varied among the ages and flocks, being most consistent in flocks 1 and 6. Eggs were collected from the flocks at the ages of 19, 26, 37, 50 and 60 weeks. Traditional egg quality measurements were determined using specialized equipment supplied by TSS UK. There was a significant effect of flock age for all egg quality measurements. With advancing hen age, egg weight increased and shell weight, percentage shell, shell thickness and yolk colour varied, whereas shell breaking strength, shell deformation, albumen height and Haugh units decreased. Cuticle cover was measured using MST cuticle stain and a hand-held Konica Minolta spectrophotometer. Cuticle cover varied with hen age, being highest at 37 weeks of age for all flocks combined. For all ages combined, cuticle cover was highest for flock 6. Maintaining high flock uniformity results in improved eggshell quality.