What is the primary function of the shell gland in a hen's reproductive system?

The primary function of the shell gland in a hen's reproductive system is to produce the eggshell. Located in the uterus or shell gland region of the hen’s reproductive tract, this organ plays a crucial role during the egg-laying process. After the egg white and yolk are formed, the egg moves into the shell gland, where the shell is formed primarily from calcium carbonate. This process involves layering the shell around the egg for protection and strength, which is essential for the developing embryo inside the egg when incubation begins.

The other functions, while important in the overall reproductive process, are performed by different parts of the hen's anatomy. For instance, providing nutrition to the embryo occurs once the egg is fertilized and incubated, while transporting the egg is facilitated by the oviduct. Storing sperm is the function of the hen's sperm storage tubules, not the shell gland. Therefore, the production of the eggshell is a distinct and vital role of the shell gland in ensuring the viability of the egg as it develops.