The aim of this study was to evaluate the effect of size initial live body
weight and feed restriction on productive performance and fertility duration of laying
hens at the end of first year production. A total number of ninety-six of Gimmizah
laying breeders (56 weeks of age similar hatching) was taken pedigree closed flock,
and was classified according to initial body weigrt (X ± 1.0 SO) into three category
 groups (32 hens of each), where heavy body weights averaged (2.136kg±0.136);
medium body weight (1.866±0.099) and light body weight (1.626=0.139) . Each
category group was divided randomly into sub grolJp (48 hens of each). The first sub-
group fed ad-libitum a commercial layer ration with 16.13% CP and 2702.2 K cal
ME/Kg feed and the other sub- group fed restricted diet to maintain breeder
recommended body weight targets. All birds were individually cages housed. These
results indicate that: - Layer feed ad-libitum system increased significantly (P<0.001)
both finial body weight; weight gain; egg number; egg weight and egg mass g/day;
but reduced duration of fertility during laying period production as compared with
layer feed restriction system. Heavy birds decreased significantly (P<0.01) egg
number; hen day percentage compared with the rnedium and light body weight. but
egg weight and feed intake were increased. however duration of fertility was not
affected by category initial body weight. Live boc'y weight was significant (P positive correlation with egg weight, feed intake and feed conversion (g feed / g egg)
. while insignificantly negative correlation with egg number and duration of fertility.
Duration of fertility was Significant (P<0.01) positive correlated with egg mass g/day,
while it negative correlated with feed convers on (g feed / g eggs). Multiple
regression coefficients was significant (P fertility was 9.467 ± 0.0699 days. Fertility percentaqr- dropped by 6.355 percent / day
to reach 50 percent at ten days and zero perce it at 15 days after termination of
artificial insemination. Conclusively it may be concluded that in tiallive body weight in Gimmizah
laying hens did not effect on duration of fertility. but effect on productive performance
only. However feed restriction system increased duration of fertility and declined egg
production at the end of first year production. Also fertility percentage declined with
increasing interval between termination of artificial ilsemination in Gammizah laying
hens. So high fertility rate is archived in artificial insemination when it is performed
twice per week