Poultry Judging Practice Test

Which section of the reproductive tract is responsible for shell formation?

1. Infundibulum

2. Isthmus

3. Uterus

4. Vagina

The correct answer is: Uterus

The section of the reproductive tract responsible for shell formation is the uterus. In chickens, the uterus, also known as the shell gland, plays a crucial role in the final stages of egg development. This is where the egg spends the majority of its time forming its hard shell, which is predominantly composed of calcium carbonate. The layers of the shell are secreted and assembled during the time the egg is in the uterus, typically taking about 20 hours. In contrast, other sections of the reproductive tract have different functions. For example, the infundibulum is involved in the initial capture of the ovulated yolk and is also where fertilization occurs if sperm is present. The isthmus facilitates the formation of the inner and outer shell membranes, but it is not responsible for the formation of the hard shell itself. The vagina plays a role in the laying process, guiding the egg out of the reproductive tract, but does not participate in shell formation. Thus, among the options provided, the uterus is the specific section that creates the protective shell around the egg.