Right now, according to government surveys, about a quarter of the cut-up chicken you buy — and about half of all ground chicken — is contaminated with salmonella bacteria.
It's a surprisingly high number, and it was a surprise to the USDA's food safety officials, too, when they realized this about a year ago. Because up to that point, their efforts had been focused on whole chickens, rather than the cut-up parts.
There's a legal limit on the percentage of whole chicken carcasses that can be contaminated with salmonella.