Sexing on down and feather colour in the Dandarawi Egyptian breed

1. The study was on a population of the Egyptian local strain Dandarawi. Ha tching records were obtained from three lines over two generations (1996 an d 1997). Sex ratios were calculated using a total of 5822 1-d-old chicks. 2. Sex could be identified at hatch by down colour. Female chicks showed a black spot on the head or irregular strips on the back, whereas males had n o marks on head and back. At 8 weeks of age, progeny could be easily sexed by feather colour, which was black and white for males and brown for female s. The sexual dimorphism in feather colour at that age is due to the presen ce of the autosomal recessive wild type allele CO*N. Accuracy for autosexin g at hatching time was 89.02% for males and 92.42% for females. 3. Sex ratio deviated significantly from the expected value, 1: 1, in one l ine (line E) where the number of female chicks exceeded that of males, over the two generations. Chicks of both sexes exhibited the same survival rate up to 8 weeks of age.