872 EXPERIMENT STATION RECORD. [Vol. 43 



How to cull a flock of hens, B. Alder {Utah Sta. Circ. 42 (1920), pp. S-8, 

 figs. 5). — The author describes the physical characteristics that are supposed to 

 indicate laying ability in hens. 



A istudy of selections for the size, shape, and color of hens' eggs, E. W. 



Benjamin {New York Cornell Sta. Mem. 31 {1920), pp. 189S12, pi. 1, figs. 57).— 

 This .study of egg characters with reference to the season of year, age of hens, 

 .size and vigor of chicks, and transraissibility to offspring was begun in 1911 

 with the incubation of 4.")0 Single Comb White Leghorn eggs selected for 

 diversities in size, shape, and color. The chickens raised were mated in various 

 ways and records were made of the characteristics of their eggs and the eggs 

 laid by their descendants in several generations. Weight was used aS a measure 

 of size and the width-length index as a measure of shape. Color was deter- 

 mined by comparison with a set of 17 sample egg-shells arranged in order 

 from chalk-white to brown, and the rank of the sample shell most closely 

 resembling the egg to be graded was used as the numerical expression for the 

 color of the latter. The results are presented in over 100 correlation tables, 

 and a bibliogi-aphy is included. 



It was found that egg-weights increased during the pullet year and thei-eafter 

 remained practically constant. There were no consistent differences in shape 

 between the eggs of pullets and the eggs of hens. Whatever the age there 

 seemed to be a tendency for the eggs laid in the spring to be rounder than 

 eggs produced at the beginning or the end of the laying year. Spring eggs 

 were also of lighter color. Eggs laid by hens 2 years of age or older were 

 darker in tint than those laid by the same birds when pullets. Eggs laid by 

 a bird after a rest period of several days were in general heavier, narrower, 

 and more darkly colored than eggs laid after several days of consistent pro- 

 duction. 



A special study was made of the 1911 and 1912 hatches to determine the 

 relationship between egg-weights and the weights and growth of the chicks. 

 The correlation between egg-weight and the weight of the day-old chick was 

 +0.844±0.021 in 1911 and 4-0.745±0.017 in 1912. The correlations were lower 

 for older chicks but remained positive and with a few exceptions significant 

 throughout the recorded ages (through 128 weeks). The correlations between 

 egg-weight and estimates of the vigor of the chicks at different ages were also 

 positive. Egg-weight seemed without definite influence on the fertility and 

 hatching percentages. 



In the inheritance studies, which were mainly Galtonian in viewpoint, a 

 hen's personal capacity in the matter of egg size, shape, or color, as determined 

 by averaging the measurements of all her eggs, is termed her life mean for 

 the character in question. In the case of a first generation cock the measure- 

 ments of the egg from which he was derived constituted his life mean, and 

 in the case of a later generation cock the average of the life means of his sire 

 and dam was taken as his life mean. The correlation between life means of 

 the daughters and the life means of their sires was found to be 0.36±0.04 in 

 the case of egg size, 0.21±0.07 in the case of shape, and 0.53±0.03 in the case 

 of color. The corresponding correlations between daughters and dams were 

 0.22±0.05, 0.47±0.06, and 0.67±0.03, respectively. The correlation between the 

 average size of the eggs laid by a hen and the size of the egg from which she 

 was hatched was found to be higher than the correlation between her average 

 egg size and the average size of her dam's eggs, and about equal to the corre- 

 lation between her egg size and her sire's life mean for size. Correlation 

 between the average shape of a hen's egg and the shape of the egg from which 

 she was derived was intermediate between the two " inheritance " correlations 



