Broiler Performance and Hatching Egg Weight to Marketing Weight Relationships of Progeny from Standard and Dwarf Broiler Dams

The relationship between egg weight and broiler weight from standard-sized and closely related dwarf dams was studied. Regression analysis of broiler weight on egg weight indicated each gram of presetting egg corresponded to 10.7 and 6.0 g additional broiler weight for males and females, respectively. Significant (P<.05) positive, linear relationships were detected between egg weight, chick weight, percent hatch weight, and broiler weights and gains. For both sexes, in four trials and at two ages, the mean weights of standard dam progeny were larger than dwarf dam progeny. The final weight (Day 49 or 50) difference between broilers from the two dam types averaged 78 g for males and 34 g for females. This represented approximately 1.2 days growth for males and .8 days for females. Hatching eggs laid by dwarf dams averaged 4.3 g smaller than standard dam eggs. This egg size difference accounted for approximately 59% of the male and 76% of the female final broiler weight differences. The remaining differences between standard and dwarf dam broilers were attributed to genetic factors including, but not limited to, the dwarfing gene (dw).