United States' third-largest chicken producer Perdue Foods has removed all antibiotics from its chicken hatcheries.

Eliminating the use of antibiotics in the hatchery has taken five years to fully implement and is the latest stage in the company's 12-year evolution in the approach to antibiotic use.

The company has not used antibiotics for growth promotion since 2007.

To clarify, Perdue does use an animal-only antibiotic to control an intestinal parasite and will use that antibiotic to treat and control illness in flocks when prescribed. This very limited use of antibiotics is more restrictive than the new FDA guideline and will affect only about 5% of chickens for a few weeks.

Antibiotic-free chicken is believed to account for 10% of what consumers spent on fresh chicken in 2013.