Dirty chick boxes at hatcheries can be a source of Salmonella, but the risk was still lower than expected in a study conducted at one US hatchery, according to Kathryn McCullough, a DVM candidate at North Carolina State University.

McCullough’s study was aimed at pinpointing where hatcheries need to focus their Salmonella-control efforts to prevent contamination of chicks with the pathogen.

“All of your breeder flocks are sending their eggs to the hatchery, and then those chicks hatching out are being disseminated… through the entire complex for that area. So, any disease measures that you can get under control at the hatchery are really going to have the biggest impact for that complex,” she told Poultry Health Today.

For the study, McCullough used boot swabs to sample chick boxes at a hatchery. Chicks were placed in clean boxes - boxes that were washed and dried - 2 days a week. Due to the hatchery’s schedule, however, dirty but dry boxes were used 2 other days because there wasn’t time to thoroughly wash and dry them.

To compare the two approaches, McCullough boot swabbed boxes that had been washed and dried. After chicks were placed in those boxes and delivered to the farm, the boxes were returned to the hatchery, where they were boot swabbed again before cleaning.

Salmonella-recovery rate

At the same time, McCullough sampled chick papers from placed flocks and found one of seven was positive for Salmonella. But the Salmonella-recovery rate for the dirty chick boxes was about 14 percent, which was lower than expected.

“It was surprising, actually,” she said. She would have expected a higher recovery rate from the boxes since there was a Salmonella-positive flock.

The situation is going to differ at different hatcheries, and cleaning and disinfection should not be ignored, McCullough said.

Antibiotics was one tool used to keep Salmonella at bay, but since they are no longer used by many hatcheries, other disease barriers are necessary and include good chick quality, a good breeder vaccination program so chicks have immunity from maternal antibodies and “really great biosecurity.”

The facility where she conducted the study was well run, and she saw that good biosecurity requires having everyone on board and motivated. “So, everybody can be doing their best at biosecurity and one breech is all it takes…I’d really say having that team spirit of everybody’s in it together is really encouraging to see. And that’s what I saw there.”