Antibiotics are commonly given in chicken feed or water at low doses for long periods to promote the growth of the birds. In the 1950s studies showed that animals given low doses of antibiotics gained more weight for a given amount of feed than untreated animals. Exactly how this occurs is still greatly unknown. Recent research suggests that antibiotics may promote rapid growth by altering the naturally occurring bacteria in the animal's digestive system, which play a role in metabolism and energy harvesting.
While it leads to growth efficiency, antibiotic use in animals is a serious public health concern, as it has contributed to the emergence of antibiotic-resistant microorganisms, including antibiotic-resistant food borne pathogens. In 2013, the U.S. Centers for Disease Control and Prevention (CDC) noted that 23,000 human deaths could be attributed to the development of antibiotic resistance from overuse of antibiotics, including in agricultural settings, and urged that antibiotics be used only to treat disease.
Prudent antibiotic use: Criteria key
prohibits antibiotics for growth promotion; allows non-therapeutic use of antibiotics under certain circumstances, for example, an entire flock can be treated when one animal is sick.
prohibits all non-therapeutic use of antibiotics except for in the egg and in day-old chicks.
prohibits all non-therapeutic use of antibiotics. Sick animals must be treated with antibiotics but must undergo a specified waiting period before being sold.
Prudent antibiotic use: How labels stack up against criteria
CHICKEN LABELS REPORT - Criteria: Prudent antibiotic use
subtherapeautic antibiotics are prohibited; antibiotics to prevent or control disease are not allowed; birds treated with antibiotics must not be slaughtered until at least twice the licensed withdrawal period has passed