Effect of Housing System on Egg Quality in Laying Hens

The aim of the study was to evaluate the quality of eggs from hybrids of laying hens of selected Polish breeding strains depending on their housing system. Analysis was made of eggs from KA-62, KA-42, KA-68 and KA-48 hybrids housed in three systems: cage, litter and free range. One hundred eggs, randomly chosen from each experimental group between 34 and 36 weeks of age, were evaluated for a set of physical characteristics such as weight of egg and egg fraction, percentage of main egg fractions, egg shape index, air cell height, albumen height and pH, Haugh units, yolk colour and pH, as well as shell colour, thickness, density and deformation. Caged birds produced the heaviest eggs (61.06 g) with the lowest shape index (77.86%), lightest shell (39.86) and highest percentage of albumen (57.04%) and yolk (29.89%) in the egg. The most favourable quality traits of albumen from the analysed eggs, i.e. greatest height (5.00 mm) and Haugh units (69.70) were characteristic of egg albumen from hens raised on litter. Shell quality analysis showed that the eggs of free-range birds were characterized by the highest weight of shell (5.76 g), which had the greatest thickness (360.14 μm) and density (81.01 mg/cm²). Detailed analysis of the physical characteristics of eggs from the hybrids of laying hens revealed significant (P≤0.05) differences depending on the housing system. The eggs of caged layers showed many characteristics desired by processors. Meanwhile, the eggs of hens kept on litter were characterized by dietetic properties that could meet specific needs of the consumers.