Groups of normal and dwarf breeder hens, having many full and half sibships in common, were compared in the laying period with respect to the following traits: mortality, egg production, ages at 25 and 50% production, feed required to produce a dozen eggs, proportion of eggs suitable for setting, size of eggs layed, fertility, hatchability and chicks produced per hen housed. Weights of eggs and broiler progeny from the two groups of hens were also compared. Dwarf hens required significantly less feed per dozen eggs produced and eggs from dwarf hens were generally smaller. Statistical analysis of the egg weight and body weight data indicated that smaller eggs were responsible for the reduced 56 day weights of female broilers from dwarf hens. It appeared that the normal gene is not completely dominant over the dwarf, tending to cause a 3.5 percent reduction of body weight in heterozygous male broilers from dwarf hens in addition to the influence of smaller egg size.