10 



MASS. EXPERIMENT STATION BULLETIN 420 



60 



5 5 



50 



45 



40 



3 5 



3 



2 5 



2 



I 5 



I 



CHART 3. 



MORTALITY RATES 



6 TO 18 MONTHS 



SEXES COMBINED 



1935 1936 1937 1938 1939 1940 1941 1942 

 YEAR HATCHED 



Adult Mortality Rates Between the Age of Six Months and Eighteen Months 



Mortality records were secured on a limited number of males between the 

 ages of 6 and 18 months. The males in the different experiments were usually 

 housed together in rather large units. Females were placed in the laying houses 

 at about 6 months of age. These pullets were divided into three 30 x 30 laying 



