Beneficial effects of instrumental music on the production performance of Xiandao green-shell layers housed under different stocking densities

Context : Egg production rate (EPR) is the main criteria for egg producers and egg quality is important for consumers. Exposed to music, layers kept at appropriate stocking density could display optimal production performance without compromising egg quality.Aims : This study aimed to investigate the possibility of employing instrumental music stimulus and regulating stocking density to maximise egg production performance and improve egg quality in Xiandao green-shell layers.Methods : In total, 378 30-week-old layers were randomly distributed into nine treatments across three types of sound sources (natural sound, instrumental music, or mixed road noise) x three different stocking densities (4, 7 and 10 birds/cage corresponding to low, medium, and high density respectively), with six replicates per treatment. The 24-day experimental period was equally divided into four phases. EPR, average egg weight, and serum IgG concentration were determined at the end of each phase. Egg quality and organ indices were determined at the end of experiment.Results : Hens exposed to music had a significantly higher EPR and laid eggs of better quality than did hens subjected to mixed road noise. Across all parameters, hens exposed to music did not significantly differ from hens exposed to natural sound. Stocking density had significant impacts on EPR, relative eggshell weight, and serum IgG concentration, with hens kept at high stocking density (357 cm(2)/hen) exhibiting the lowest values. Hens kept at medium density (510 cm(2)/hen) and low density (892 cm(2)/hen) showed no significant differences in tested parameters except that the former produced eggs with a significantly higher relative eggshell weight. Significant interactions between sound and density were observed in EPR, relative yolk weight, and spleen index, with hens exposed to music and kept at low density displaying the highest values.Conclusions : Music and low stocking density had favourable effects on improving egg production and egg quality, while road noise and high stocking density exerted negative influences on them.Implications : Xiandao green-shell layers are recommended to be kept at medium density to maximise the production benefits. The integration of music playback into management practices will not compromise layers' production potential displayed under natural sound exposure.