Non-typhoidal Salmonella enterica is a leading cause of foodborne illness in humans, primarily transmitted through contaminated eggs. This study investigated the prevalence and serovar distribution of Salmonella in commercial layer farm environments and day-old chicks in Korea. Salmonella were identified in 26 (65.0%) of 40 farms and 47 (62.7%) of 75 flocks, and the prevalence of Salmonella in farms and flocks was highest in environmental dust (57.4% and 54.7%), followed by feces (42.5% and 34.7%) and feed inside house (20.5% and 34.7%) (p < 0.05). Moreover, Salmonella were detected in two (8.7%) of 23 external silo feeds. In chick box papers, Salmonella were identified in 14 (66.7%) flocks. The most significantly observed serovar in environmental dust was S. Thompson (16.0%), followed by S. Colindale (12.0%), and most common serovar in feces was S. Colindale (9.3%), followed by S. Agona (6.7%) and S. Thompson (5.3%). Interestingly, S. Colindale was also detected in one (1.4%) of 23 external silo feeds. The most prevalent serovar in chick box papers was S. Colindale (28.6%), followed by S. Senftenberg (14.3%). In particular, S. Colindale was detected in chick box papers of flocks derived from three of 6 hatcheries (10.0%-75.0%) and two of 4 breeds (25.0% and 66.7%), and S. Thompson was detected in chick box papers of one (4.8%) of 21 flock. S. Enteritidis was detected in environmental dust from one (1.3%) flock, and S. Typhimurium was not detected.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    Sample collection
    Isolation and identification of Salmonella spp.
    Statistical analysis
RESULTS
    Prevalence of Salmonella in commercial layer farmsand flocks
    Prevalence of Salmonella in day-old chicks
    Distribution of Salmonella serovars in commercial layerflock
    Distribution of Salmonella serovars in day-old chicksby hatchery origin
    Distribution of Salmonella serovars in day-old chicksby breed origin
DISCUSSION
REFERENCES

• Soo Kyung Park(College of Veterinary Medicine & Institute for Veterinary Biomedical Science, Kyungpook National University, Daegu 41566, Korea)
• Jae Kyung Lee(College of Veterinary Medicine & Institute for Veterinary Biomedical Science, Kyungpook National University, Daegu 41566, Korea)
• Young Ju Lee(College of Veterinary Medicine & Institute for Veterinary Biomedical Science, Kyungpook National University, Daegu 41566, Korea) Corresponding author
• Hak Sun Yu(Department of Parasitology and Tropical Medicine, School of Medicine, Pusan National University, Yangsan 50612, Korea)