112 MASS. EXPERIMENT STATION BULLETIN 211. 



Table III, — Statistical Constants for Certain of the Flocks — Concluded. 

 Age at Fihst Egg (Days). 



1 Means calculated from grouped data instead of ungrouped as in Table II. 



In Fig. 8 certain changes in winter production of selected groups are 

 given, comprising, first, the highest record made in each season by any- 

 one individual; second, the best average record made by the daughters 

 of any one mother, provided not less than five daughters comprised the 



•i3-if "is-'ie %-'n 17-18 'is-'ig 



YEAR 



•|9-'20 



■20-21 



Fig. 8. — Winter Production. 

 Broken line, best individual; solid line, best average made by daughters of one female; 

 dotted line, best average made by daughters of one male. 



group; and third, the best average record made by the daughters of any 

 one male for each season, provided that he had ten or more daughters. 



Changes in Mean Annual Production. 

 Annual production is the number of eggs laid in the first laying j'ear, 

 beginning with the first egg and running 365 days therefrom. Barring 

 longevit}^, it is probably the best inde.x of a bird's innate lajdng capacity. 



