Abstract
Erythrocyte (RBC) count, packed cell volume (PCV) and haemoglobin (Hb) values were found to be higher in Nigerian domestic fowls than those in Hubbard fowls. PCV and Hb values were higher in males than in females in both breeds. Erythrocytes of the Nigerian fowl were observed to be more susceptible to osmotic haemolysis than were erythrocytes of the Hubbard fowl. Erythrocytes of male fowls were osmotically more fragile than were those of female fowls in both breeds.