Poultry Judging Practice Test

During incubation, which membrane surrounds the embryo and is located next to the shell?

1. Amnion

2. Chorion

3. Yolk sac

4. Allantois

The correct answer is: Chorion

The chorion is the correct choice because it is the membrane that surrounds the embryo in avian eggs and is located directly next to the eggshell. During embryonic development, the chorion plays a crucial role in gas exchange. It is responsible for facilitating the transfer of oxygen into the egg and carbon dioxide out, allowing the developing embryo to breathe. Additionally, the chorion works with other membranes, such as the allantois, which collects waste and also assists with gas exchange, and the amnion, which provides a protective fluid-filled sac around the embryo. However, the key aspect defining the chorion's role is its proximity to the eggshell, making it distinct from the other membranes present during incubation. The amnion primarily serves as a protective layer that contains fluid, while the yolk sac provides nutrients to the embryo and the allantois handles waste and respiration. Each of these membranes has a specific function, but the primary feature of the chorion is its location next to the shell, allowing essential interactions for the embryo's development.