The native Ogol fowl, which is a protected species under the Korean government (Protected Species Act No. 265), has not been accepted as a breed because of insufficient research. Its external features include black colouring of the beak, eyes, face, earlobes, wattle, tongue, shank, toes, feathers, skin and bones. Average weights of males and females at hatching are 32.0 and 29.6 g, respectively. Sexual maturity is reached at about 24 weeks of age, but growth continues to around 500 days. Age at first egg averages 167 days and production is about 100 eggs annually. The weight of the edible parts is 60–63% of the total body weight. Fertility rates reported range from 76.4% to 82.2%, while hatchability ranges from 74% to 79%. The paper includes haematological data together with heritability estimates for traits of economic importance.