June 1941] Agricultural Research in New Hampshire 39 



One hundred sixty-four ornamental woody plants, representing 

 131 species and varieties, are being studied to obtain hardy strains 

 with low susceptibility to diseases. 



Lilac breeding and selection are being conducted to develop types 

 of superior quality for New England. The present collection consists 

 oi 171 plants, representing 108 hybrid types, and 22 species and varie- 

 ties. As a result of treatment with colchicine, several seedlings are 

 apparently tetraploids. 



Data on the common house plants are also being gathered. 



(Bankhead-Jones and Hatch Funds) 



POULTRY 



Protein Requirements of Chickens (R. C. Durgin, T. B. Charles, S. 

 R. Shimer, and H. A. Davis) 



This study of the protein requirements of chickens was begun in 

 1935. Two groups of birds were carried in batteries and laying cages 

 for a period of 70 weeks each, while a third group in floor pens was 

 checked for 70 weeks. 



It was found that as the protein content of a ration increased 

 from 15 to 19 per cent, a definite increase in body weight occurred in 

 chicks fed this ration. No relationship was apparent between per- 

 centage of protein and total feed consumption, but a very definite 

 correlation was found between total feed consumed and total body 

 weight attained during the experimental period. 



Chicks receiving the protein mixture and fish meal supplement 

 were significantly heavier in weight at 12 weeks of age than were 

 the chicks fed meat scrap or dried skim milk. Generally, the birds 

 receiving the lower protein rations were the most efficient in feed 

 utilization during the growing period. The groups receiving fish 

 meal as the sole source of animal protein were found to have a higher 

 average rate of production of eggs and produced a greater number 

 of eggs per bird than other groups. They were also lowest in feed 

 cost per dozen eggs produced, and earliest in sexual maturity. There 

 appears to be no correlation between the protein content of the ration 

 fed and the size of eggs, or the age at which the chickens laid their 

 first eggs. 



A record of the hatchability of the eggs from these groups was 

 also kept, and gizzard erosion was studied in all the chicks that 

 hatched. It was found that as the percentage of protein in the meat, 

 fish and mixture groups was increased, the gizzard linings improved 

 noticeably, showing less gizzard erosion. In the birds fed dried skim 

 milk, an increase in the level of protein resulted in the gizzard condi- 

 tion becoming progressively worse. 



(Purnell Fund) 



Selective Breeding as a Control of Disease (R. C. Durgin, T. B. 

 Charles, C. L. Martin, and C. A. Bottorfr) 



