This study evaluated the effects of dietary inclusion of sun-dried and blanched avocado (Persea americana) leaf meal (ALM) on growth performance, haematological indices, and oxidative stress biomarkers in broiler chickens. One hundred and eighty broiler chickens were randomly assigned to nine dietary treatments: control (T1), sun-dried ALM at 0.25% (T2), 0.50% (T3), 0.75% (T4), and 1.00% (T5); and blanched ALM at 0.25% (T6), 0.50% (T7), 0.75% (T8), and 1.00% (T9) in a completely randomized design. Growth performance parameters (final body weight, body weight gain, feed intake, feed conversion ratio) were monitored from days 28-56. Haematological parameters (PCV, RBC, WBC, Hb, platelet counts, differential leukocyte counts, MCH, MCHC) and oxidative stress markers (superoxide dismutase, glutathione peroxidase, catalase, malondialdehyde, total antioxidant capacity) were determined at the end of the experiment. Results showed no significant differences (p>0.05) in growth performance parameters across treatments, although T5 (1% sun-dried) numerically improved body weight gain (466.67 g). Haematological parameters revealed significant treatment effects: PCV ranged from 34.00% (T9) to 54.00% (T6); WBC ranged from 2400.00×10³/μL (T1) to 4500.00×10³/μL (T9); and haemoglobin ranged from 11.30 g/dL (T9) to 17.65 g/dL (T7). The 1% blanched ALM (T9) induced haematological alterations characterized by reduced PCV, RBC, and Hb, and elevated WBC. Catalase activity was significantly higher (p<0.05) in T3 (0.162 U/mg) and T8 (0.162 U/mg). Malondialdehyde concentrations were significantly reduced (p<0.05) in T3 (0.317 V/mg), T8 (0.295 V/mg), and T9 (0.320 V/mg) compared to control (0.526 V/mg). Dietary inclusion of sun-dried ALM at 0.5-1.0% and blanched ALM at 0.5-0.75% supported broiler performance comparable to control and enhanced antioxidant capacity by reducing lipid peroxidation and improving catalase activity. However, 1% blanched ALM induced adverse haematological effects, indicating a threshold-dependent toxicity. Blanched ALM at 0.5-0.75% inclusion is recommended as the optimal processing method and inclusion level, while sun-dried ALM can be effectively utilized at up to 1.0% inclusion without adverse effects.