A total of 280 straight-run day-old Cobb broilers were used to determine the effect of supplementing basal diet with plant extracts (PE) on nutrient metabolizability and production performance. Birds in Treatment 1 were given the control diet while those in Treatments 2, 3 and 4 were given basal diet supplemented with PE at 75, 100 and 125 g/ton of feed, respectively. Following a 42-day feeding period, metabolizability of nutrients, body weight gain, feed consumption, feed conversion ratio (FCR), dressing percentage, livability and intestinal villi height were determined. Results showed no significant differences (P>0.05) in all production parameters measured among treatments except for FCR during the 7-28 days feeding period (P<0.05 ). Feed supplemented with 75 g/ton had the best FCR, which was higher than the control by 11 points while feed supplemented with 125 g/ ton reduced FCR by 16 points. Addition of PE improved the average villi height. The results of the study suggest that feed supplemented with 75 g/ton can enhance the performance of broilers.