Poultry Judging Practice Test

The term that describes the small, white spot on the yolk of an infertile egg is known as the blastodisc. This disc appears on the surface of the yolk and is the structural part that would develop into an embryo if fertilization were to occur. In the case of an infertile egg, this blastodisc remains small and undeveloped. In contrast, the germinal disc refers to the specific area of the yolk where fertilization takes place and is associated with the potential for development. The chalaza is a rope-like structure that helps keep the yolk centered within the egg's white, while the shell membrane is the thin layer just inside the eggshell that provides protection and serves as a barrier to microorganisms. Knowing these definitions helps clarify why "blastodisc" is the correct term for the described characteristic of an infertile egg.