Ninety-six day old Lairier cockerel chicks were used in an experiment to evaluate the after effects of detoxifying (soaking, boiling, addition of riboflavin and glycine to antagonize hypoglycins) dietary Blighia sapida (ackee apple) seed meal, BSSM. Blood chemistry, haematology, liver morphology indices which dietary BSSM influenced and reflected in the performance characteristics of the cockerels investigated in a single-factor experimental design experiment were assessed. Results showed that the residual phytotoxins of BSSM, hypoglycins A & B with their metabolite MCPA at 17.50% inclusion of the processed BSSM in diets elicited reduction in glucose, protein, albumin, globulin while elevating blood cholesterol, creatinine, urea,total and conjugated bilirubin relative to the reference diet (p <0.05).Dietary BSSM similarly increased the transaminase activities of AST/SGOT, ALT/SGPT including ACP (p < 0.05). BSSM based diets also caused significant reduction in PCV, RBC, WBC, Hb as well as MCV, MCH and MCHC similar to the results obtained on WBC differential counts of neutrophils and lymphocytes in comparison with the conventional diet (p < 0.05). Histopathological examinations on the liver samples revealed that the control diet presented livers that were normal in tissue morphology without inflammation or haemorrhage while the photomicrographs of the liver samples of cockerels fed treated dietary BSSM at 17.50% inclusion showed morphological patterns indicating severe distortion suggesting evidence of haemorrhage and inflammation with numerous blood cells occupying the available hepatic sinuses. The poor results recorded on the biochemical, haematological and morphological parameters were reflected in performance characteristics as reduced feed intake, weight gain, growth rate, feed efficiency and high mortality were obtained on diets containing BSSM compared with the orthodox diet (p < 0.05). Findings of this experiment indicated that for optimum results, processed BSSM be included in diets below the 17.50% level considered high for the birds in this study.KEYWORDS: Cockerels, BSSM, treatments, blood chemistry,haematological and performance indice