Forty-eight 154-d-old White Leghorn hens were fed a diet containing 0 (control), 0.5, 1.0 and 1.5% bamboo charcoal powder including vinegar liquid (SB). Compared with the control group, production performance in the SB groups did not differ. Egg production tended to be increased in the 0.5 and 1.0% SB groups, but decreased in the 1.5% SB group; the former two groups were higher than the latter (P