This study aimed to evaluate the replacement of soybean meal by detoxified castor bean meal on the intake and digestibility of nutrients, body weight gain, carcass yield, physiological and urinary parameters, and creep-feeding method effectiveness. For this trial, 43 male lambs were used, Dorper × Santa Inês, with an average initial body weight of 7.95 kg, 15 days old. Lambs were distributed in a randomized block design. Five experimental diets were provided: Without supplementation, with supplementation but without the use of castor bean meal, and with gradual levels of replacement of soybean meal by detoxified castor bean meal (33%, 67%, and 100%). Higher values of DMI and nutrient digestibility (p < 0.05) were observed for animals that received supplements. The milk intake did not differ among the diets. The DMD showed a linear effect, while NDFD had a quadratic effect, depending on castor bean meal inclusion. The carcass yield did not differ between experimental diets. There was no significant effect on the urinary volume and metabolites investigated. In conclusion, the replacement of soybean meal by detoxified castor bean meal does not compromise animals’ development. Besides, the creep-feeding method positively affects lamb development, with higher body weight gain for supplemented animals.