ANNUAL REPORT, 1Q41 97 



were started, the first from females la\'ing but few eggs during molt and the 

 second from females laying for a relatively long period during the molt. Pre- 

 liminary studies over three years indicate that the ability to lay eggs and molt 

 simultaneously is a highly desirable trait. The change in body weight of males 

 and females during the annual molt is not very significant. Males already used 

 required an average of about 94 days to shed their wing primaries while females 

 averaged about 1 19 days. Some females lay very few eggs during this period while 

 others lay up to 40 or 50 eggs. Good females should shed at least three primary 

 wing feathers before laying stops. Completion of wing molt in December appears 

 to be desirable from the standpoint of first-year egg production. 



Miscellaneous Genetic Studies. (F. A. Hays.) Linkage studies include genes 

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

 An effort is also being made to isolate the sex-linked gene for early sexual maturity. 

 A new method for separating sexes in Rhode Island Red chicks is being studied 

 and offers some possibilities. For auto-sexing, a gold-barred bird is being de- 

 veloped on a limited scale. 



The Use of Crab Meal in Poultry Rations. (Raymond T. Parkhurst and 

 Marie S. Gutowska with C. R. Fellers of the Departnient of Horticultural Man- 

 ufactures cooperating.) In broiler production studies, Red-Rock cross chicks 

 were used and comparisons involved the 1940-41 New England College Con- 

 ference starter as the basal ration, the basal ration with 5.5. percent crab meal 

 replacing 2.5 percent fish meal, the basal ration with 5.5 percent crab meal re- 

 placing 5 percent milk and 2.5 percent fish meal, and the basal ration with 3 

 percent fish meal replacing 5 percent of dried skimmilk. The mineral contents 

 of the rations were adjusted. There were no significant differences in growth, 

 mortality, feed efficiency, feathering, or pigmentation. 



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

 2.5 pounds) in the Massachusetts complete all-mash laying ration, there were no 

 significant differences in egg production, weight of eggs, feed efificiency, yolk 

 color, albumen quality, fertility, and hatchability. The egg production av- 

 eraged higher in the fish meal group, based on the birds that lived, but fewer 

 birds died in the crab meal group; with the result that total production, total 

 income, and the feed cost per dozen eggs were practically the same for the birds 

 on the two rations. The results to date show that crab meal is a satisfactory 

 ingredient in poultry rations and can replace fish meal on an equal-protein basis. 

 Further comparisons of these feeds are in progress. 



The Manganese Requirements of Laying Hens. (M. S. Gutowska and R. T. 

 Parkhurst.) The effect of the addition of manganese to complete all-mash laying 

 rations was investigated from a practical standpoint. Forty-eight Rhode Island 

 Red pullets were kept on a basal all-mash ration for 12 lunar months (2 periods 

 each lasting 6 lunar months). The two high-manganese groups received in their 

 diets 76 and 61 parts per million of manganese; the two low-manganese groups, 

 17 and 24 p. p. m., respectively. The data showed no appreciable differences in 

 egg production, feed efficiency, fertility, hatchability, and livability between the 

 compared groups; but the shell-breaking strength of eggs laid by the pullets on 

 high-manganese rations was significantly greater than that of eggs laid by birds 

 on the low-manganese rations, although the shell texture was not unsatisfactory 

 in the latter groups. It was concluded, because all-mash lajang rations contain- 

 ing as little as 17 and 24 p. p. m. of manganese did not produce manganese 

 deficiency symptoms in laying hens in a period of 12 lunar months, that even 

 these levels in laying rations can be considered satisfactory from a practical 

 viewpoint. 



