A method for separating sex-linked imperfect albino (S*ALS) and nonalbino embryos before hatch

The feasibility of using the sex-linked gene for imperfect albinism (S*ALS) to sex chicks during incubation by candling was studied. With this technique, the dark eye of nonalbino embryos can be positively identified. Two trials were performed. In a first trial, 66.5 and 89.5% of the 254 nonalbino and 210 albino chicks produced in four hatches were correctly identified by candling at 7 d of incubation. Of 191 eggs predicted to be nonalbinos, 22 were albinos, resulting in an overall accuracy of 88.5% for identification of nonalbino embryos. In a second trial, the accuracy of the technique from 7 to 10 d of incubation was evaluated. Increased age resulted in a tendency for lower accuracy, but candling at 8, 9, or 10 d of incubation allowed identification of a greater (P < 0.05) proportion of the nonalbino population than at 7 d of incubation. Candling at 8 d of incubation allowed identification of nonalbinos and albinos with an accuracy of 81.3 and 84.9%, respectively, suggesting that the ALS gene could be used to sex chicks during incubation when used in a sex-linked cross. This technique may prove advantageous to the laying industry because of savings of incubator and hatcher space. The males of commercial layer lines are normally killed at hatch. Reducing the number that hatch by eliminating them before 10 d of incubation could diminish animal welfare concerns.