Normality of some quantitative traits in chickens

Abstract

1. Distributions of some economically‐important traits in two strains of White Leghorn chickens over six generations were examined. 2. Negative skewness and positive kurtosis were observed for egg production whereas age at first egg showed positive skewness, reflecting an excess of undesirable birds in both the cases. Body weight and egg size showed little or no departure from normal distributions. 3. Such deviations from normality as skewness and kurtosis are associated with characters of relatively low heritability which are more prone to environmental effects. Extremes of gene frequencies and non‐additive genetic effects may also contribute to deviation. 4. Positive kurtosis and skewness cause decreased selection intensity.