Evaluation of adult and juvenile selection schemes for improving part year egg production of egg type chickens

Date on production traits of egg type chickens undergoing selection for egg number upto 40 weeks of age during 1999–2004 were utilized for the study. The production traits viz. 20 week body weight (BW₂₀), age at first egg (AFE), egg weight (EW) and egg number upto 40 and 50 weeks of age (EN₄₀, EN₅₀) recorded on individual pullets were subjected to statistical analysis for estimating genetic and phenotypic parameters. These parameters were utilized to evaluate the adult and juvenile selection scheme to improve egg number upto 40 and 50 weeks of age. The results revealed that expected response in egg number (both EN₄₀ and EN₅₀) from juvenile scheme was higher than that obtained under adult scheme. However, decline in age at first egg and egg weight was expected to be less in adult scheme than from juvenile scheme. Because of about 7 times higher costs and space required for juvenile scheme than in adult scheme limits its use in practice.