Agricultural Research in New Hampshire 61 



tion. Birds with a strong agglutination reaction in dilutions of 1 to 20 

 or higher do not show the characteristic leucocytosis following 

 inoculation. 



When an artificial air cell was made on the side of eggs produced by 

 inoculated hens we were able to isolate the virus from the embryo and em- 

 bryonic membranes of many of them. The virus was present in 80 per 

 cent of all eggs examined two months after the hens had been inoculated, 

 and in 20 per cent five months after inoculation. We have also been able 

 to isolate the virus from 2 of 24 eggs examined from a flock where the 

 disease was reported to be present. 



In all we have been able to isolate this infectious agent from birds 

 originating from four separate poultry farms and from the eggs of a fifth 

 farm. All give the same type of gross lesions in the eggs and in suscepti- 

 ble birds. Serum from a bird injected with any of the strains will aggluti- 

 nate an antigen made with any of the five strains. Intranasal, intratra- 

 cheal, and intracutaneous injections have eliminated the possibility of 

 bronchitis, laryngotracheitis and fowl pox. Birds with a positive aggluti- 

 nation titer to this Bluecomb virus are susceptible to larnygotracheitis and 

 fowl pox. (E. F. Waller, A. E. Tepper, R. B. Halpin, H. A. Davis) 



Influence of Size of Eggs on Hatchability, Rate of 

 Growth, and Feed Consumption of Crossbred Broiler Chicks 



Two pens of approximately 125 New Hampshire females on the 

 University Poultry Farm were mated with mature Barred Plymouth Rock 

 males for the production of crossbred hatching eggs. Starting on October 

 15, 1941 all eggs laid by these birds were weighed and sorted into groups, 

 weighing, respectively, 20-21, 22-23, 24-25, and 26 ounces and above until a 

 maximum of 360 eggs per group were selected. On October 29 these re- 

 spective groups of eggs were incubated and the resultant chicks brooded in 

 separate floor pens for a period of twelve weeks. 



All chicks were fed the New England College Conference chick 

 starting ration. Starting at eight weeks of age two pounds of cracked 

 yellow corn was fed daily per 100 birds to all groups. Feed consumption, 

 mortality, and growth records were maintained weekly. 



The hatchability of these eggs for all groups was very good, ranging 

 from 77.8 to 85.0 per cent of total eggs set. It is to be noted that the 24- 

 25 ounce egg size group showed the, highest per cent of hatchability, 

 whereas those eggs 26 ounces or over in weight per dozen gave the low- 

 est percentage hatchability. This same relationship holds true when the 

 ratings are based on per cent hatch of fertile eggs. Here, however, the 

 range is from 82.11 per cent to 92.16 per cent, nearly a ten per cent 

 differential. 



Upon the completion of the hatch a random selection of 225 day- 

 old chicks from each group was made. These chicks were placed in 

 similar brood pens 12 feet by 24 feet in size and heated by a continuous 

 hot water system. The birds were maintained in these same pens without 

 culling for a period of twelve weeks. 



It was evident that large chicks will ordinarily result from the hatch- 

 ing of large eggs. However, this initial advantage is not necessarily 



