Previous research has demonstrated the role played by boron in the synthesis of estrogens, vitamin D and other steroid hormones and, therefore indirectly in bone matrix mineralisation. The study presented concerns the effects of different source and levels of boron on the mineralisation of bony tissue. Experimental work involved the preparation of fixed histological samples of tibial tissue from sampled broiler chickens in five experimental treatment groups: the feed concentrate (FC) of the control group (1) was not boron supplemented; group 2 were received 20 mg B/kg FC in the form of boric acid; group 3–20 mg B/kg FC as phosphate glass; group 4–10 mg B/kg FC in the form of calcium fructoborate; group 5–10 mg B/kg FC as phosphate glass. Histomorphometric parameters evaluated were the volume of bone trabeculae (BV/TV, %) and mean bone trabecular thickness. Histomorphometric analysis of transverse sections of the proximal extremity of the tibia showed that bone trabeculae volume (BV/TV, %) was greater for groups 4 (52.87%) and 2 (50.19%). The ratio was 43.22% in the control group, 45.70% for group 3 and 45.57% or group 5.