Antibiotic Free.
A product can be labeled ABF as long as the animal is free of antibiotics at the time of harvesting.
However, it is common practice to take a sick animal out of the herd, administer antibiotics until the animal is well again, and then return the animal back to herd (after the antibiotics have left the animal's system).
The next level of ABF means no antibiotics have been administered ever. In this scenario, a sick animal is removed from the herd, treated, and often returned to a different herd or utilized for another purpose.