The study evaluated whether a single oral administration of lectin extracted from common beans (Phaseolus vulgaris) at 12 weeks of age influences intestinal morphology and bone structure in roosters and capons. A total of 320 male birds were allocated to four experimental groups based on hormonal status and lectin treatment. Birds in the lectin-supplemented groups received a single gastric dose of lectin at 100 mg/kg body weight. Growth performance, carcass traits, intestinal histomorphometry, and tibial geometry and mechanical properties were assessed at 24 weeks of age. Lectin administration induced significant changes in jejunal morphology, with the most pronounced effects observed in capons. These effects were less pronounced in hormonally intact roosters. The effects on bone were limited and included slight differences in marrow cavity dimensions, without improvements in mineralization or mechanical strength. The findings indicate that a single oral dose of lectin primarily affects intestinal structure under conditions of androgen deficiency, whereas its influence on bone properties remains modest. Further studies are required to determine the optimal dosing strategy and the potential relevance of lectin supplementation for practical poultry production.