What is the age at which peak shedding occurs in laying hen flocks infected with Salmonella enteritidis?

• A. 12 weeks
• B. 24 weeks
• C. 18 weeks
• D. 30 weeks

Answer: (C)

Peak shedding in laying hens infected with Salmonella enteritidis occurs when the birds begin to lay eggs, about 18 weeks of age. This timing matters because the reproductive tract becomes active, providing a route for Salmonella to ascend into the oviduct, which not only increases internal infection but also leads to shedding in feces and potential contamination of eggs. The host’s immune system is still adapting to the infection at this stage, and production-related changes in the gut and oviduct create conditions that favor higher levels of shedding. As hens move further into the laying period, shedding can level off or decrease as immunity develops and production environments change, but the initial surge aligns with the onset of lay, around 18 weeks.