1. Key Laboratory of Chicken Genetics and Breeding, Ministry of Agriculture, Harbin 150030, Heilongjiang, P.R. China
2. Key Laboratory of Animal Genetics, Breeding and Reproduction, Education Department of Heilongjiang Province, Harbin 150030, Heilongjiang, P.R. China
3. College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, Heilongjiang, P.R. China