comparison of growth performance of six commercial broiler hybrids in iran

an investigation was carried out to evaluate the growth performance of six commercial broiler hybridsavailable in iran (arbor acres, arian, cobb 500, hubbard, lohmann and ross 508). two hundred and fiftyfertile eggs of each hybrid were taken from different breeder farms, all over the country. the similarity offlocks ages and their health conditions were considered. after hatching, the sexed chicks were randomlyassigned to six replicates of floor pens of 17 chicks, except the male cobb hybrid which had five replications.all groups were managed in a similar way throughout the 56 days of study. daily feed intake (fi) and dailybody weight gain (bwg) were measured on weekly basis and the european production index (epi) werecalculated at 49 and 56 days of age. there were no significant differences among hybrids in fi during starterand grower periods (p>0.05), although significant differences were observed in finisher period (p