H A ri-: ()i- I \^ INC \N!) i:(i(; ruonrc rioN ih'a 



cfifi-liiyiiij:' (■(intfst.s ;i>- \m-I1 .i^ in m.-ikiiij: iiji lirccdiiifi Hock.s iiiul (•(iinriicr- 

 (•i;il prodnrtidii fl()ck>. Tlu' v.iliic of cnlx scmi.iI iiiiitiirity in flock seloc- 

 titiii ha.s ;ilTr,i(l\ Ix't-ii ]M)int»'d out (ll;iys and IW-iiiu'tt, Ift'iH), yet scxnal 

 inatnrit> is inadf(|uate as tiie soli- ;iiii(i<- of tlic l)ii'cdt"r in ins selections. 

 If siinic sliort-tinie test can be diseox trt-d, its luactical worth is self-evident. 

 A poimlation of 'Jiifjo birds is studied ovef the i)eiiod from Ifllfi t(> 

 I !>•_'."). The si\t\-ii,i> eiifi record of each individual is tabulated ajtainst her 

 jiroduetion for the remainder of the scar, a time interval of MD.t days. 

 Constants obtained follow: 



Number of birds 2o<j(> 

 Mean sixty-day record 37. 8() 



.Sixty-day record standard deviation it9.94 



.Mean subsequent annual record lti.27 



Subseciuent annual production standard deviation — ■tO.O+ 

 Coefficient of correlation -f-.3082 ±:.0121 



Comparinii the variability in sixty-day record with the variability in 

 rubseijuent annual record, the coefficients of variability are 26 per cent 

 ;Mid 28 ])er cent, respectively. Theoretically, tbe standard deviation in 

 rmnual record should be five times as great as tbe standard deviation in 

 sixty-day record because the time interval of the former is ien months, and 

 of the latter two montlis. In reality, the two constants are about the 

 same, showiiifi that egg production fluctuates most during the early months 

 of the pullet laying year. 



A positive coefficient of correlation of ..■J082 ±.0121 indicates a signif- 

 icant tendency for heavy sixty-day production to be associated with heavy 

 jiroduction for the remainder of the year. The degree of correlation is 

 somewhat less than the — .1380 ±.0131 reported by Hays and Bennett 

 Moc. cit.) between age at first egg and annual egg yield. The probabilities 

 are that selection upon first sixty days' record as a partial measure of 

 intensity, and upon age at first egg as a?iother valuable criterion, will in- 

 crease fecundity. 



B. MEAN WINTER CLUTCH SIZE. 



An expression for the clutch si/e of a pullet furnishes information rela- 

 tive to iier ability to elaborate few or many eggs on successive days. In 

 other words, it is an index to functional capacity. Mean clutch size 

 tliroughout the winter season otters ])ossibilities as a measure of intensity 

 over a considerable period of time. Moreover, clutch size can also be 

 (Icfinilely measured for each individual and measurable characteristics are 

 most useful in biological studies. 



Behavior of Clutch Size in Inheritance. 



.V frecjuency distributi<m of any of the flocks included in tin's report with 

 regard to clutch size clearly presents a bimodal aspect. A more exact 

 classification of each individual bird for clutch size places the modes at a 

 clutch size of 2 and 2.2, respectively. There is a very pronounced depres- 

 sion in the frequency .sraph at the clutch size of 2.1. The freciuency dis- 

 tributicm for clutch sizes from 1 to 2 rather closely approaches a straigrht 

 line with a positive slope not far from 1. On the other hand, frequency 

 (iistribuf ion for clutches greater than 2 is less regular and if fitted to a 



