Te 6 th International Seminar on Tropical Animal Production Integrated Approach in Developing Sustainable Tropical Animal Production October 20-22, 2015, Yogyakarta, Indonesia 391 Analysis of Reproductive Potential and Hatchability of Naked Neck and Normal Hens Jafendi H.P.Sidadolog, Tri Yuwanta, Wihandoyo, Sri Harimurti, Sri Sudaryati Heru Sasongko and Bambang Ariyadi Faculty of Animal Science, Universitas Gadjah Mada, Yogyakarta, Indonesia Corresponding email: sidadolog04@yahoo.com ABSTRACT: The difference between a feather conditions, namely naked neck and normal feathered in chicken gives the qualitatively genetic differences by Na gene and its allele na. This study was conducted to analyze the relationship between the condition of the feather and of reproductive potential. Five males of Naked neck, each paired with four females of Naked neck and two females of Normal. Production of eggs from each female were collected and then incubated, to studies the reproductive potential through egg fertility and hatchability. Completely randomized designs by the variance analysis were used to determine the effects of the feather conditions, and the hierarchical analysis of variance was to determine of the genetic potential. The results showed that the feather conditions did not signifcantly affect the egg production. The fertility of naked neck chicken (95.72±03.88%) was signifcantly higher (P<0.05) than normal chicken (92.67±10.61%) and the hatchability of naked neck chicken (73.69±21.69%) was signifcantly lower (P<0.05) than normal chicken (83.76±04.84 %). Embryo mortality of naked neck chicken (19.85±11.04%) was signifcantly higher (P<0.05) than normal chickens (17.97±11.50%). Eggs weight and doc weight did not show a signifcant difference. Heritability of egg weight in chickens was low (h² = 0.07), and the repeatability (R = 0.69) was quite high. The heritability of doc was underestimated (h² = -0.19), although the repeatability was still high (R = 0.59). Keywords: Naked Neck and Normal Native Chicken, production, reproduction, repeatability and heritability. INTRODUCTION Local chicken (Native Chicken) is a native Indonesian germplasm assets are very valuable. Its presence there was almost total throughout the countryside in Indonesia. Experts agree that today’s modern chickens (layers and broilers) is a descendant of the red jungle fowl (Gallus Gallus gallus = bankiva) that originating from Southeast Asia (Scannes et al. 2004; North, 1984 ), and some experts said that since 5000 years BC domestication process had begun in Indonesia (Abelein, 1986 cit. Sidadolog, 2011). Local chickens grow and develop in according to the process of adaptation to the environment. Domestication process resulted in some changes morphologic as a result of natural selection to survive in harsh environments. The change caused of a very extensive phenotypic diversity and the ranging of the difference in weight, production and reproduction until the coat color and body as well as the shape and the structure of the body. The variation of local chickens became so widespread, for example in the form and body size, shape of comb, color, growth and spread of coat color. One variation that is often found in the critical and hot conditions was the lake of feather growth on the neck, which was then referred to the Naked Neck Fowl. The naked neck feathered is a genetic trait controlled by autosomal genes Na-, as a dominant against its allele na (Devenport, 1914 cit. Rajkumar et al. 2009). Naked neck trait was inherited to the offspring with proportions