A selection program for four generations (base and three selected generations) was started in 2011 at Benha
University, Egypt to improve growth traits in a synthetic line named Benha chickens. A total of 18 cockerels and
180 pullets were selected according to their BLUP values for egg number during 90 days of laying from Benha
base population (control). Data of 4916 chicks produced by 69 sires and 484 dams were used to estimate
heritabiliets, genetic and phenotypic correlations and BLUP estimates for body weight at 0 (BW0), 4 (BW4), 8
(BW8), 12 (BW12) and 16 (BW16) weeks of age along with daily gains during 0-4 weeks (DG4), 4-8 weeks
(DG8), 8-12 weeks (DG12) and 12-16 weeks (DG16). The selection effects, correlated responses and the genetic
and phenotypic trends for body weights and daily gains across generations were quantified or clarified applying
the updated approach of the animal model program of BLUPF90. Heritability estimates were moderate or high;
being 0.52, 0.28, 0.27, 0.33 and 0.31 for BW0, BW4, BW8, BW12 and BW16, respectively. Genetic correlations
for growth traits at different ages were positive and ranged from 0.64 to 0.88 among body weights, and from 0.14
to 0.65 among daily gain traits. The ranges in BLUP of most body weights and gains in the control generation
were higher than those in the selected generations. Accuracies of BLUP estimates for growth traits in all
generations (control and selected) were moderate or high. The three selected generations were superior (P