This research was organized to determine the effects of the applications of choice feeding on the performance of broilers and to measure abilities of broiler to compose their own diets. Fattening was divided to four periods and broilers were fed starter diets during first period. At 15 d the broilers (at begining of 3 rd week) were transfered randomly to pens and started different feeding treatments. There were eight feed treatments: broilers were fed on soybean-maize based control diet at treatment 1, wheat based diet at treatment 2, diets mixed whole wheat instead of ground wheat in wheat based diet (10 % at second period, 20 % at third period and 30 % at fourth period) at treatment 3, diets mixed whole wheat instead of ground wheat in wheat based diet (15 % at second period, 25 % at third period and 35 % at fourth period) at treatment 4, choice feeding between ground wheat and blancer diet A which were composed with omited the ground wheat from the wheat based diet at treatment 5, choice feeding between whole wheat and blancer diet A at treatment 6, choice feeding between ground wheat and blancer diet B which were composed with omited the ground wheat and maize from the wheat based diet at treatment 7, choice feeding between whole wheat and blancer diet B at treatment 8. The differences among the groups were insignificant for the live weight at the end of the experiment, the average live weight gain and the feed conversion ratios at 3-6 wk period of age (P>0.05), however, the differences among the groups were significant for the average feed consumption (P<0.05). The average wheat preferences in choice feeding groups (5, 6, 7 and 8 th groups) were respectively 43.5, 43.4, 61.5 and 45.4 % (P<0.01) during the experiment. At the end of the experiment, four broilers of each sex which were selected at random from each group were slaughtered. The differrences among the groups were insignificant for dressing pertentage, crop, preventriculus, pancreas, abdominal fat weights (P>0.05), however, the differences among the groups were significant for gizzard and digestible system weights (P<0.05).

Layer breeder, performance, pure line, genotype