2.1 │ Sample origin
The positive rates of virus isolation and p27 antigen in breeding eggs of an indigenous chicken were both within 1% for two consecutive generations. In order to introduce new genes, the introduction of Hy-line brown fast feathering roosters and artificial insemination were performed. Ever since, about 7.61% (7 from 92 samples) were found to be p27 positive in the albumen samples. Therefore, semen and plasma samples from the same males (46 samples), plasmas from hens (92 samples) and albumens from the five ALV positive hens (10 samples) were collected for virus isolation of for ALV, respectively.