308 MASS. EXPERIMENT STATION BULLETIN 259 



Weight at Sixteen Weeks of Age 



Data are available on the sixteen-week weight for only two years — 1918 

 and 1921. A wide variation in mean weight in the two years is evident. A 

 total of 1245 males averaged 1574.0 grams; the 1397 females averaged 1226.0 

 grams. Males were 28.38 per cent heavier than females. The total population 

 of 2642 birds gave an average of 1390.0 grams. 



Card and Kirkpatrick {loc cit.) present records on 288 pullets at 16 

 weeks. These pullets averaged 1318.6 grams. 



Kaupp (Joe. cit.) gives the average weight of both sexes at 16 weeks as 

 1510.5 grams. The average weight of males he gives as 1633.0 grams and of 

 females as 1415.2 grams. His males were 15.39 per cent heavier than the 

 females. 



Jull and Titus {loc. cit.) report the mean weight of 77 cockerels at 16 

 weeks as 1852.0 grams, and of 72 pullets as 1506.6 grams. The average of 

 the 149 birds was 1685.1 grams. 



In general, the data indicate that the Rhode Island Reds studied at the 

 Massachusetts Station were somewhat smaller at 16 weeks than those of Card 

 and Kirkpatrick, Kaupp, and Jull and Titus. The males at Massachusetts 

 were 28 per cent heavier than the pullets, while the males weighed by Kaupp 

 were only 15 per cent heavier than the females. 



Weight at Twenty-one Weeks of Age 



Both males and females were weighed individually when 21 weeks of age 

 for the six-year period from 1923 to 1928. Table 1 shows the number of birds 

 weighed and the mean weight each year. Only minor fluctuations appear from 

 year to year. It is very significant that the mean weight of both males and 

 females in 1928 was almost the same as was recorded for 1923. A rather 

 wide gap exists between the mean weight of males and females throughout 

 the period. The summary shows that the 3105 males averaged 2400.1 grams, 

 and that the 3836 females averaged 1905.7 grams. The males were 25.94 per 

 cent heavier than the females. 



Card and Kirkpatrick {loc. cit.) report the mean weight at 21 weeks of 

 251 Rhode Island Red pullets as 1746.8 grams which appears to be a rather 

 low weight. 



Kaupp {loc. cit.) gives the average weight at 21 weeks as 2041.2 grams. 

 The mean weight of males in Kaupp's flock was 2272.5 grams, and the mean 

 for females was 1846.2 grams. The males were 23.09 per cent heavier than 

 the females. 



Available data indicate that Rhode Island Red males at 21 weeks of age 

 weigh about 2300 grams or about 5 pounds; that females weigh about 1900 

 grams or about 4.1 pounds; and that n;ale& average about 25 per cent heavier 

 than females at this age. The fact that the Massachusetts strain has been 

 bred for early sexual maturity along with heavy body weight probably ac- 

 counts for the superior weight of these birds at 21 weeks. They were some- 

 what smaller than either those studied by Card and Kirkpatrick {loc. cit.) or 

 by Kaupp {loc. cit.) at 16 weeks. 



