In a recent publication, Consumer Reports examined over 300 chicken breasts from grocery stores across the country. The report revealed horrifying quantities of many different strains of harmful bacteria, some of which were antibiotic resistant varieties.
It turns out that during an in ova vaccination process, the hatcheries for the chicken factory farms inject a small amount of antibiotics. This process also occurs in the eggs which eventually hatch out the chicks intended to be grown on organic feed and labeled 'Organic.'
Apparently, if the resulting chicken meat is to be sold using the label, 'No Antibiotics,' this practice of injecting antibiotics cannot occur. In farming facilities in which this practice does occur, a 2007 peer-reviewed study determined that workers were 32 times more likely than their neighbors who didn't work in the poultry industry to be carrying gentamicin-resistant E. coli bacteria.
For those of us that raise our own chickens for eggs and even meat, the news is a reinforcement that dense animal management is too intensive to produce a product without creating problematic residue.
To read more about this, take a look at Tom Philpot's Mother Jones article detailing the practice of in ova antibiotic injections and assessing the impact of subjecting even minute amounts of antibiotics to our most popular meat.