Spatial Variability of External Egg Quality in Vertical Naturally Ventilated Caged Aviaries

SIMPLE SUMMARY: The external quality of eggs is an essential factor to consider in the poultry production sector since economic losses are directly related. This study evaluated the spatial variability of external egg quality in naturally ventilated vertical caged aviaries, with variability in quality hypothesized to be caused by hen age differences and by variability in thermal and light conditions within the aviary. Both winter and summer conditions in a tropical region were examined. The spatial variability of external egg quality was found to be greater in summer than in winter, regardless of hen age. Egg weight and shell quality values were lower in the upper level of cages located in the center of the aviary. The light intensity in the aviary presented tremendous spatial variability, but its effect on external egg quality was not significant. Egg external quality spatial distribution determination is shown to be a useful indicator of economic loss and an aid in hen nutritional and thermal management, as well as in egg collection and classification, by deploying a differentiated management of collection in the area where hens produce eggs with lower external egg quality. ABSTRACT: External egg quality is an essential parameter of egg production as it relates directly to economic losses. This study evaluated the spatial variability of external egg quality in five naturally ventilated caged vertical aviaries. Differences caused by bird age and thermal and luminous variability within aviaries during winter and summer were analyzed. Data on aviary air temperature, relative humidity, light intensity, and external egg quality were collected at evenly distributed points along the aviary length within three levels of cages. The experimental design was completely randomized in a factorial scheme. In the summer, the highest air temperature and lowest relative humidity were found in central cages, mainly in upper center cages; hens produced eggs with a lower weight and shape index in this area. Similar results were obtained in the winter. In the summer, eggs with lower shell weight and thickness were also produced by hens housed in the central cages, but in the winter, the opposite result was obtained. This study of the spatial variability of external egg quality proved efficient in detecting areas within an aviary with poor quality eggs; improvements to design and management in these areas could help management improve production efficiency and contribute to a sustainable egg supply.