Variations in Egg-quality Characters in Certain Breeds, Varieties, and Strains of Chickens

Kecent trends in research in the field of egg quaUty have been toward the study of the initial condition of the egg rather than the changes that occur during holding periods under varying environmental influences. Most investigators have concerned themselves largely with the so-called interior egg-quality characters and more particularly with the albumen portions of the egg. Practically all such studies have been confined to single strains of a breed or variety with little or no evidence as to the comparability of different breeds, varieties, and strains. Hoist and Almquist U) ^ demonstrated that percentage of firm albumeo in the egg is a characteristic dependent on the individual hen. Lorenz, Taylor, and Almquist {6) gave further evidence of this and bred families of Single Comb White Leghorn that differed significantly with respect to this character. Van Wagenen and Hall (11) confirmed these findings and further showed that characteristic individual differences exist with regard to the score of the condition of the firm albumen, percentage apparent (outer) thin albumen, percentage inner thin albumen, yolk index, and yolk color. Knox and Godfrey (5) found a significantly greater percentage of firm albumen in the eggs of the White Leghorn than in those of the Rhode Island Red, and suggested that such differences might be influenced by proper selection. Wilcke (14) observed that eggs from individual inbred hens were more uniform with respect to the combined viscosity of the entire contents of the egg than were eggs from noninbred birds. Hainan and Day (3) concluded from a candhng study of the eggs laid at the West Suffolk Egg Laying Trials during 1931-34 that there is no correlation between productivity of the bird and egg faults (meat spots, blood spots, watery whites, dropped yolks, and deformed -shells). They also observed that the occurrence of a particular type of fault appears to be definitely finked with the individual bird rather than with external conditions, and has been shown to be associated more with certain strains than with others. Since the egg-quality studies conducted at this station have been, in the main, with a single strain of birds, it was desired to secure