A selection study for improving eggshell colour in two parent lines of laying hens and their hybrids

AbstractThe aim of this research was to evaluate selection studies towards increasing eggshell colour intensity and homogeneity, without reducing egg production of brown-egg-laying hens at the Poultry Research Institute of Ankara, Turkey. This study was based on data obtained from 1342 pedigree Barred Rock-1 (BAR-1), 1158 pedigree Rhode Island Red-1 (RIR-1) and 611 hybrid (RIR-1xBAR-1 or ATAK-S) brown laying hens, where eggshell colour and egg production performances were determined. Hens were selected for dark, uniform shells and egg production performance, as paternal and maternal lines from RIR-1 and BAR-1 base populations. Colour coordinates; L* (brightness), a* (red/green scale), b* (yellow/blue scale) and eggshell colour index (SCI) were determined. The values of L*, b* and a* were significantly changed during the study. The estimated heritabilities for BAR-1 hens of egg weight (EW), L*, a*, b* and SCI were as follows: 0.62, 0.64, 0.62, 0.55 and 0.32; The RIR-1 hen values were as follows: 0.51, 0.74...