How is Salmonella pullorum transmitted?

Salmonella pullorum is primarily transmitted through eggs and shell contamination, which is why the second choice is the correct answer. This bacterium can be present in the reproductive system of infected hens and can be transmitted to the eggs during their formation. When eggs are laid, they may have the bacteria on their shells or within them if the hen was infected. The contamination can occur externally on the eggshell or internally if the bacteria pass through the hen's reproductive tract into the egg itself.

Understanding this transmission route is critical for poultry showmanship because it emphasizes the importance of biosecurity and hygiene practices, such as proper handling and sanitation protocols for eggs and nesting areas, to prevent the spread of Salmonella pullorum within flocks. It also highlights the significance of testing and monitoring egg layers for the presence of the bacteria to ensure safe production.