Effects of genotype and age on egg quality traits in crossbred chickens developed for backyard poultry farming

The experiment was conducted to study the effect of genotype and age on egg quality traits in four different crosses viz. PD1 X PD4 (PA), PD1 X PB2 (PB), PD1X PD3 (PR), PD1X IWI (PW). The egg qualities were measured in 20 eggs each of each cross at 28, 40, 52 and 64 weeks of age. The genotype significantly (P<0.05) affected egg weight and shell thickness at all the ages of measurements, whereas, significant (P<0.05) differences for shape index, albumen index and Haugh Unit were observed for 28, 52 and 64 weeks of age only. Colour index and yolk index were significant (P<0.05) between crosses at 52 and 64 weeks of age. Albumen, yolk and shell % differed significantly (P<0.05) between crosses at 28, 40, 52; 28, 40 and 28 weeks of age, respectively. Age effect was significant (P<0.05) for all the egg quality traits in all the crosses except for yolk colour where it was significant (P<0.05) for PW birds only. Egg weight increased as the age advanced and most of the egg quality parameters decreased at older ages. Yolk % and shell % increased at older ages but albumen % decreased. Shell thickness increased at older age of measurement. PA recorded better shell thickness which may be a useful trait to lower breakage during handling of eggs compared to other crosses. The study concluded that genotype and age significantly (P<0.05) affected different egg quality traits measured at different ages in all the four crosses.