An experiment was conducted to evaluate the effect of multivitamins (Vi) or vitamins mix with acid amin (ViA) in drinking water on growth performance and feather pecking rate of Hisex Brown chicks during brooding stage until 9 weeks age. A total of 2,070 chicks at one day of age was allocated in 3 treatments and 3 replications. The experiment was arranged in completely randomly design into 9 pens (230 chicks/pen). The treatments were: 1) Control treatment (Cont): Basal feed (B) without any supplemented product in drinking water; 2) MV: B+Vi at 1ml/l of drinking water; 3) MVA: B+ViA at 1ml/l of drinking water. The results showed that the final live weight of chicks in treatments supplemented with Vi (912.3 g/bird) and ViA (924.5 g/bird) were higher than the chicks in control group (852.1 g/bird). The average weigh gain (ADG) of chicks in supplemented treatments was higher than that in control group. Average feed intake (AFI) did not difference between the treatments. Lead to FCR was lowest in MVA (2.30kg), next to  the chicks fed MV (2.36kg), and highest in Cont (2.44kg). The morbidity rate and death rate of chicks in the MV treatment was lowest, and highest in control group. Feather pecking rate was lower in chicks fed supplemented treatments to compare with control chicks, in which chicks in MVA was lowest. In general, supplementation with multivitamins or vitamins mix with amino acid products at the level of 1ml/l of drinking water improved average daily gain, feed conversion ratio and feather pecking rate of Hisex Brown chicks during brooding stage until 9 weeks age.

Key words: Amino acid, brooding stage, growth performance, multivitamins, Hisex Brown, feather pecking rate.