Abstract: An experiment was conducted to assess the effect of feed form on performance, gastrointestinal development and carcass traits of broiler chickens. A total of 270 days old male Ross 308 broiler chicks were assigned to three dietary physical forms with six replicates of 15 birds each. The physical forms of diets including: mash and pelleted forms fed from 1-42 days of age, whereas the third treatment received crumbled and pelleted during 1-14 and 14-42 days of age, respectively. Feed intake, body weight gain, feed conversion ratio, performance index and production number were significantly (p<0.05) improved in pelleted or crumblepellet diets fed birds over mash fed birds. The survivability was significantly (p<0.05) higher in mash fed birds, as compared with pelleted fed birds (94.9 vs. 88.1%), but not differed with crumble-pellet fed birds. Carcass yield, breast, thigh, liver, heart, pancreas and abdominal fat weights as a percentage of live body weight were not affected by physical form of diets. Gizzard and caeca weight as a percent of body weight, were significantly (p<0.05) heavier in mash fed birds, over pellet or crumble-pellet fed birds, whereas crop, proventriculus and small intestinal weights were similar in all birds.