Salmonella and it causes are very regional in EU. Places like Finland have basically 0 cases of salmonella caused by domestic poultry products per year. If there salmonella is found from any chicken in the flock, the whole flock will be quarantined and generally fully slaughtered (meat & eggs must be pasteurized after the slaughter if they are sold). In 2023 0.1% of the tested flocks had salmonella.

According to https://pmc.ncbi.nlm.nih.gov/articles/PMC11945640/ most of the outbreaks in humans (where exact cause was found) were caused by foreign vegetables.

On other hand countries like Italy find positive samples from 27% of their flocks ( https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa... ). USA doesn't do testing at that level as far I understand, I only found that 8% of the tested chicken parts have salmonella (https://www.propublica.org/article/salmonella-chicken-usda-f...).