56 MASS. EXPERIMENT STATION BULLETIN 398 



months-old male began with 100 percent fertility, declined to 74 percent in mid- 

 June, but returned to 100 percent fertility in late July. The young male (12 

 months old) showed consistent fertility throughout the 10-week period, but his 

 record was never equal to that of the 24-months-old male. On the female side, 

 yearling hens were consistently higher in fertility than either old hens or pullets. 



Miscellaneous Genetic Studies. (F. A. Hays.) Linkage studies between 

 genes for shank feathering, comb form, and mottled ear lobes in Rhode Island 

 Reds will soon be concluded. The dominant sex-linked gene has been eliminated 

 so that stocks of crossbreds that carry only the autosomal gene E' are being 

 developed. Progress is being made on a new method for separating the sexes in 

 Rhode Island Red Chicks on the basis of down color. A gold-barred strain is 

 being developed for auto-sexing chicks. The effect of ultra-violet irradiation on 

 mutation rate is being studied. Selective breeding for abnormal sex-ratios is 

 being carried on. 



Alkaline Phosphates and Egg Shell Formation. (Marie S. Gutowska and 

 R. T. Parkhurst, with the cooperation of E. M. Parrott and R. M. Verberg of 

 the Chemistry Department.) Studies were conducted to throw more light on 

 the question whether or not alkaline phosphatase is a factor in egg shell forma- 

 tion. It was found that: 



1. The physiological mechanism of the deposition of calcium in the egg 

 shell was independent of a local phosphatase activity factor in the shell gland 

 (uterus) of the hen. 



2. The phosphatase activity in the blood plasma of the laying hen seemed to 

 be related to a definite genetic constitution of the hens — high productivity and 

 good egg shell strength. 



3. The deposition of calcium in the egg shell was based on a different mechan- 

 ism than the calcification of the bones. 



4. Phosphatase activity was very low in the shell gland, in the oviduct, and 

 in the ova of the laying hens as well as in their bones at the tmie of shell forma- 

 tion. It was considerably higher in the blood plasma, coming within the lower 

 range found in human blood. 



5. The necessary transformation of the colloid compound containing calcium 

 and phosphorus, and yielding calcium for the egg shell, appeared to take place 

 in the blood itself; the shell gland acting, probably, only as an excretory organ 

 for calcium. 



Crab Meal as a Replacement for Fish Meal in the Laying and Breeding Ra- 

 tions. (Raymond T. Parkhurst and Emery J. Jefferson with C. R. Fellers of the 

 Department of Horticultural Manufactures cooperating.) In further studies in 

 which crab meal replaced fish meal on an equal-protein basis (4 pounds for 2.5 

 pounds) in the Massachusetts complete all-mash laying ration, corn dried dis- 

 tillers grains with solubles, corn distillers dried solubles, and fermentation sol- 

 ubles (with soybean oil meal) also replaced all the dried skimmilk in the ration. 



The results confirmed previous conclusions that crab meal can replace all of 

 the fish meal in the ration used, in which adjustment was made for the higher 

 mineral content of the crab meal. Comparable egg production, egg weight, body 

 weight, feed consumption, feed efficiency, egg quality, hatchability and chick 

 quality were also obtained when the distiller^' and fermentation by-products 

 replaced the dried skimmilk. 



In the groups with Red-Rock crosses, the percentage hatchability of fertile 

 eggs was higher for the rations containing skimmilk than for those containing 

 distillers dried solubles, whether used with fish meal or crab meal and, in both 

 cases, was higher for fish meal than for crab meal. For Rhode Island Reds, the 



