Abstract：There are two major methods to introduce exogenous substances like foreign DNA into the chicken embryo. One is microinjection of the foreign DNA into the subgerminal cavity of fresh fertilized eggs before incubation. The other is microinjection of the foreign DNA into the yolk sac vein vessel after the fertilized egg incubated for 72 h. Workload, technical difficulty, effectiveness, and the hatchability of recipient chickens were listed as criteria to evaluate the two methods. The results indicated that the former way was easier to conduct but with a lower hatchability of 9.5%. The foreign DNA could be found in the recipient embryos of different ages and the chicks after hatching; The latter way was relatively difficult but with a higher hatchability of 35.7%. The foreign DNA could be found in the recipient embryos of different ages and the chicks after hatching, also without integration. Which way to be selected depends on the aim of the experiment, action time of the exogenous substances and the sample size.
