Haematological Parameters of Indigenous and Exotic Chicken Breeds Under Tropical Conditions in Ogun State

This study compares haematological parameters of indigenous Nigerian chickens and Cobb 500 exotic broilers raised under comparable management conditions in Ogun State, located in Nigeria's South West geopolitical zone. Haematological profiles reflect physiological adaptation to environmental conditions and disease challenge, and establishing breed-specific reference ranges under tropical management is important for poultry health monitoring. Forty indigenous and 40 exotic chickens aged 8 weeks were sourced from farms in Abeokuta and managed under identical housing, feeding, and health care conditions for four weeks. Blood samples collected by venipuncture were analysed for packed cell volume, haemoglobin, red blood cell count, white blood cell count, differential leucocyte count, mean corpuscular volume, mean corpuscular haemoglobin, and thrombocyte count. Results revealed that indigenous chickens had significantly higher packed cell volume (32.4%) and haemoglobin concentration (11.8 g/dL) than exotic breeds (27.1% and 9.6 g/dL respectively), suggesting superior erythropoietic capacity under tropical heat stress conditions. Lymphocytes dominated the leucocyte differential in both breeds. Heterophil to lymphocyte ratio was significantly higher in exotic breeds, indicating greater physiological stress responses. No significant differences were found in platelet counts. The study establishes haematological baselines useful for veterinary assessment in Ogun State and supports the nutritional and health resilience advantage of indigenous breeds under Nigerian tropical conditions. Keywords: haematological parameters, indigenous chickens, exotic breeds, Ogun State, tropical poultry.