Studies on the influence of juvenile growth traits on laying performance in egg type chickens

The influence of juvenile growth traits on laying performance was evaluated based on the data obtained on body weights at 4, 16, 40 and 56 weeks of age, on shank length at 4 weeks and on hen housed egg production (HHEP) at 40 and 56 weeks in pure line layer strains (IWH and IWI). Body weight at 4 of age was positively correlated with egg production to 40 weeks of age (rg=0.43 in IWH line and rg=0.99 in IWI line). Positive correlations were also obtained with shank length (SL) at 4 weeks and body weights at 16 and 40 weeks of age. Heritability (h²₅) of 4 week body weight is 0.31±0.14 in IWH and 0.39±0.06 in IWI. Relationship of 16 week body weight with egg production was similar to 4 week body weight and this body weight is medium heritablity trait. Higher body weight at 4 weeks is related to early commencement of the flock, in to production, better continuity in lay and has better livability during the period of lay.