During which period are chickens 100 to 1,000 times more susceptible to Salmonella enteritidis?

• A. Molting
• B. Laying
• C. Brooding
• D. Hatchling

Answer: (A)

During molting, chickens experience a dramatic shift in physiology and immunity that greatly lowers their defenses against Salmonella enteritidis. Feather shedding and regrowth, plus reduced feed intake and overall stress, push the bird into a catabolic and nutrient-deprived state. Hormonal changes raise stress hormones that suppress immune function, and gut mucosal defenses become weakened. The combination of a disrupted gut barrier and altered microbiota creates an environment where Salmonella can colonize and invade more easily, resulting in the infection risk increasing by a hundred to a thousandfold compared with other periods. While other life stages have their own risks, the molt uniquely combines stress, immune suppression, and gut vulnerability to produce the highest susceptibility.