Whilst the potential of Cu supplementation of broiler diets in excess of their requirement as a alternative animal growth promoter (AGP) has been investigated, little research has been done to determine whether short time supplementation of extra level of Cu will affect broiler performance at market ages. This experiment was carried out to investigate the effects of feeding three level of copper (0.0, 125, and 250 mg supplemental Cu/ kg diet from cupric sulfate pentahydrate; Cu. SO4. 5H2O) in excess of the requirement during starter period(1 to 21 day of ages) on subsequent performance, relative weight (%) of gastrointestinal organs, and abdominal fat in broiler chicks. A total of one hundred and fifty six day-old Ross 308, broiler chicks (mixed sex with similar ratios) were allocated to three treatments, each replicated four times (52 chicks per treatment) in a completely randomized design. Chick’s body weight, daily gain, feed intake and feed conversion ratio (FCR) were determined at weekly intervals. At 7, 21 and 49 days of ages, the body length, weight, and body mass index (BMI) of all chicks were measured individually. The results indicated that the broiler body weight at 7, and 14d, average daily gain during 1 to 7d, 7 to 14d and 1 to 20day; average feed intake during 1 to 20 and 1 to 42 day of ages were all significantly decreased with feeding 250 mg per kg extra level of copper. The results showed that the FCR during 21 to 42 day of ages were insignificantly improved by feeding 125 mg/ kg of copper in excess of requirement, compared to control and 250 mg/ kg copper fed counterparts. Broiler individual body weight and BMI at 7, and 21 day of ages and body length at 7 and 21 day of ages were also significantly decreased by feeding extra level of copper during starter period. The relative weight of different gastrointestinal organs, bone characteristics, and Cu concentration of fresh liver ware not significantly affected(P>0.05) by different dietary treatmen
