308 HARRIS, KIRKPATR1CK, BLAKESLEE, WARNER AND CARD 



Comparison of the four periods as bases for the prediction of the egg record 



of the year 



In the introductory sections of this paper we called attention to the so- 

 called periods or cycles of egg production which have been recognized by 

 a number of students of fecundity in the domestic fowl. It might at first 

 seem desirable to compare the results of predicting from these periods. 



Since these periods are consecutive and together make up the entire 

 laying year it is impossible to obtain any common basis for testing their 

 efficiency such as has been found in periods of subsequent months in pre 

 ceding tests. 



In view of this fact it does not seem desirable in this place to go into the 

 question of the comparison of these conventional periods as bases of pre 

 diction. Practically all of the data required for such comparison as can 

 be made appear in the foregoing tables 2 to 13. The reader who desires 

 to do so may abstract the constants from these tables. 



SUMMARY AND CONCLUSIONS 



The specific purpose of the present paper, which is one of a series dealing 

 with the general problem of variation and correlation of egg production 

 in the domestic fowl, is to consider the possibility of predicting the future 

 egg production or the total annual egg production of White Leghorn birds 

 from the record of an individual month or a group of consecutive months. 



The investigation has been carried out because of two convictions: 

 First, factors underlying the distribution, inheritance and interrelation 

 ships of fecundity in birds present a problem of first-rate biological impor 

 tance. Second, that it is one of the functions of the biologist to provide 

 the agricultural economist with the quantitative constants and formulae 

 upon which the scientific agriculture of the future must largely rest. 



The method followed has been to determine a series of prediction equa 

 tions based on the experience of six years (1911 to 1917) of the INTER 

 NATIONAL EGG-LAYING CONTEST at Storrs and to test these equations upon 

 an additional series of 415 birds studied at Storrs in 1917-1918. Thus the 

 equations have been tested upon a different series of birds from that upon 

 which they were based, but upon birds maintained under conditions com 

 parable with those upon whose record the fundamental equations were 

 based. 



The results show that the annual egg record of a series of birds may be 

 predicted with a reasonably high degree of accuracy when their performance 

 for a single month is known. Somewhat higher accuracy may be obtained 



