EGG PRODUCTION. 73 



mother and daughter in respect to egg producing abihty. On 

 the average pullets which did exceptionally well as compared 

 with the other pullets in the experiment were just as likely as 

 not to be the daughters of irothers who were exceptionally poor 

 in production as compared with other mothers in the same 

 experiment. In other words, the data so far obtained do not 

 indicate that egg producing ability is sensibly and directly 

 inherited between mother and daughter. There may be such 

 in inheritance, but further data are needed to demonstrate it. 

 The results of the present experiment tend to confirm the con- 

 clusion tentatively reached from a study of the past egg records 

 of the Station accumulated during nine years of selective 

 breeding.* 



COMPARISON OF "registered''' AND '^UNREGISTERED" PULLETS IN 

 RESPECT TO EGG PRODUCTION. 

 It was pointed out in an earlier section of this bulletin, that 

 in addition to the evidence afforded by a study of the correlation 

 "between parent and offspring light on the problem of the 

 inheritance of egg producing ability might be gained by a com- 

 parison of the egg production of birds whose mothers were 

 closely selected for high egg production with birds whose 

 mothers were not so particularly selected. Evidence from this 

 source cannot take the place of that afforded by the study of 

 correlation but it may and does supplement such evidence. 

 Besides the so-called "registered" pullets in the present experi- 

 ment there were 600 pullets which received precisely the same 

 treatment, but whose mothers were birds laying between 150 

 and 200 eggs in their pullet year rather than birds falling into 

 the "200-egg" or "registered" class. (Cf. p. 51 supra.) Of these 

 600 "unregistered" birds 100 were kept in two pens of 50 birds 

 each, exactly like the pens in which the "registered" pullets 

 were kept. Of the other 500 birds only two flocks — one of 100 

 and one of 150 birds — are available for strictly fair comparison 

 with the "registered" pullets. 



*Cf. Pearl. R. and Surface, F. M. A Biometrical Study of Egg 

 Production in the Domestic Fowl. Part I — Variation in Annual Esrg 

 Production. (In press). A brief summary of the chief results of this 

 study has been published in Me. .A.gr. Expt. Stat. Bulletin No. 157. 



