A total number of 156 hens of tow local su ains. Mandarah and Salam of 25
weeks of age were used in this study to investigate the effect of strain and some
prornc ~ers en the: performance of laying hens. Birds of each strain were randomly
div:dcd iptc, 4 gruups of 39 hens each. The first group fed a basal diet containing
15.88% CP and 2750 Kcalfkg diet. The other groL ps (2; 3 and 4) fed the basal diet
supplemented with 120 mg Flavomycin/kg diet; 1.0 g Dinaferm®/Kg diet and 1.0 g Bio-
nutra®fkg diet. respectively. Salam hens were recorded significantly (P< 0.05) higher egg production and
egg number than those of Mandarah ones from 29-36 and 25-40 wks for egg
production and from 29-36 wks for egg number. Flavc mycin treatment had the hi~hest
(P Dinaferm® groups during all the experimental periods Egg weight and egg mass were
significaniiy (P<0.05) increased in Salam hens vs. those of Mandarah ones. except
egg weight through 33-36 wks. Similar egg weight:; were observed in the different
expenrnental treatments. While egg mass in birds reated with Flavomycin or Eio-
nutra® was significantly (P<0.05 or 0.01) higher tha 1 that of Dinaferm® during 33-40
wks. Yolk and shell weights and shell thickne: s did not show any significant
difference due to strain or treatment effects. excepl for shell thickness in Mandarah
birds that had higher (P<0.05) shell thickness than hat of Salam ones. Salam birds
treated with Bio-nutra" had higher values of shell t-uckness vs. the control group.
Fertility and hatchability percentages were significantly (P<0.05) higher in Mandarah
strain than those of Salam one. while, chicks' weight at hatchin~ was signifiCcntly
(P<0.05) lower in Mandarah hens. Hens treated with Bio-nutra had the higo.st
percenta\1es of fertility and hatchability (P<0.01). Mean,vhile. birds fed Flavornycm and
Dinaferm were of lower percentages. Chicks weight ,\Id not differed significantly due
to the dietary treatment. The two strains had similar values of feed consumption during 33-40 "J~~.
while. feed consumption and feed efficiency were significantly (P Salam strain than Mandarah one during the other periods of the experiment. Feed
consumption of treated groups was significantly (P control. Birds treated with Havornycm or Bio-nutra" had the best values of feed
effioency. The interaction effects (strain with treatments) were insignificant for previous
traits. except for egg weight during 29-32 wks and shell thickness. which were
significant (P<0.05). Salam hens had slightly higher values of di ]estibility coefficients for the all
nutnents than those of Mandarah hens. The supplementation of performance