BREEDING AND GENETICS Effects of the Blue Egg Shell Allele (0) on Egg Quality and Other Economic Traits in the Chicken1

Araucana females homozygous dominant for the blue egg shell allele (O) were mated to homozygous recessive (oo) Shaver Starcross "288" males to produce F( hybrids het­ erozygous at the blue egg-shell locus. The Ft females were backcrossed to Shaver males producing full-sib sisters; half were blue egg layers and half white egg layers. The white egg layers had a significantly higher percent egg production than the blue egg layers (82 versus 79%). No significant differences between white and blue egg layers were found for shell quality, shell thickness, albumen weight, yolk weight, or yolk cholesterol. (Key words.- chickens, Araucana, shell color, egg qualities, cholesterol) 1983 Poultry Science 62:1717-1720 from hens obtained by crosses of AU X RIR showed a significant reduction in the level of cholesterol. Reports in the popular literature have suggested low cholesterol levels in Arau­ cana eggs (Hickman, 1974). The objective of this study was to determine the effects of the O allele and closely linked genes on internal and external egg quality and on reproductive performance in hens with similar genetic backgrounds.