6 MASS. EXPERIMENT STATION BULLETIN 329 



Mean egg production previous to the pause was high, considering the fact 

 that the pause may begin as early as November. Variability in production at 

 this time was very high as indicated by the standard deviation. The coefficient 

 of correlation was negative, suggesting that an increase in number of eggs 

 laid was not followed by a greater length of pause. The squared value of this 

 constant shows that less than 5 percent of the variation in pause duration 

 could be attributed to previous egg production. These data suggest that 

 pause duration is not increased either by the number of eggs laid or by the 

 rate of laying previous to the pause. 



7. Length of Previous Production Period and Pause Duration 



Early hatched pullets would normally go through a long period of egg laying 

 before March 1. For this reason it is important to know whether the length 

 of the production period previous to the winter pause affects the length of 

 winter pause. Hays and Sanborn (1926, page 173) studied this question with 

 Rhode Island Reds. Examination of their data shows that the regression of 

 pause duration on length of previous production period is not linear. The 

 data are as follows: 



Number of birds 2,078 



Previous production period, days .... 52 . 26 



Production period standard deviation, days . . ± 34 . 23 



Mean pause duration, days 31.91 



Pause standard deviation, days ±21.68 



Coefficient of correlation -.1385 +.0145 



Correlation ratio .2199 



The relation between length of the previous production period and winter 

 pause duration, as measured by the correlation ratio, was .2199. The 

 relationship was of a negative order, indicating a tendency for the pause to 

 decrease in length as the previous production period increased. Certainly 

 not more than 5 percent of the variation in pause duration was attributable to 

 variation in length of the previous production period. It follows, therefore, 

 that duration of pause was but little dependent upon the length of time that 

 the pullets had been laying. 



8. Production Following Pause and Pause Duration 



If winter pause were a recuperative period, it is conceivable that pauses of 

 greater duration might be followed by increased rate of laying and greater 

 production for the remainder of the year. In order to discover the relation 

 of egg production following the pause to duration of pause, the coefficient of 

 correlation was calculated. The following constants were derived: 



Number of birds 



Mean production following pause, eggs 

 Production standard deviation, eggs 

 Mean pause duration, days . 

 Pause standard deviation, days . 

 Coefficient of correlation 

 Correlation ratio .... 



353 



140.62 



±40.56 



34.62 



±23.08 



.0799 ±.0357 



.2377 



