LIMITED TRAPNESTING 



11 



LIMITED TRAPNESTING FOR ESTIMATING ANNUAL EGG WEIGHT 



The average weight of the eggs laid during the entire first laying year is very 

 important economically. It is desirable, however, to reduce the number of 

 weighings as much as possible without interfering with the accuracy of the 

 estimate of the annual weight. Godfrey (1933) found that the mean annual egg 

 weight may be accurately estimated from the mean weight of one egg each month, 

 the mean weight of the first ten eggs laid, the mean weight of eggs laid in March 

 and April, and the mean weight of eggs laid during the first four days of Decem- 

 ber, January, February, and March. 



Five abbreviated types of weighing have been tested for accuracy in this study. 

 Table 7 gives the correlations between the short-time weights and the actual 

 recorded average weight for the first year, the estimated weight as calculated 

 from the regression equation, and the actual weight. In Table 8 the estimated 

 annual egg weights as calculated from the regression equations are placed beside 

 the actual means. 



The results indicate that the annual egg weight may be estimated with a high 

 degree of accurac}^ by weighing eggs the first two da^-s of each month, by weigh- 

 ing eggs for the first week of each month, by weighing eggs daily during August 

 at the end of the laying year, and by weighing eggs daily from first egg to Jan- 

 uary 1. Estimates based on weights for the month of October at the beginning 

 of the pullet laying year are not very reliable. 



Table 7. — The Value of Limited Trapnesting and Weighing for Esti- 

 mating Probable Annual Egg Weight. 



* Regression was linear in all cases except the October weighing. The estimated annual egg 

 weight was calculated from the linear equation, however. 



** Weights are for the remainder of the year, and the correlation coeflScient shows the relation 

 between egg weight up to January 1 and after January 1. 



