Most worker ants are slackers.

Behavioral Ecology and Sociobiology

Researchers marked every ant in five lab-based colonies with dots of colored paint. Over the course of 2 weeks, a high-definition camera recorded 5-minute segments of the ants in action six times a day, capturing their behavior (or lack thereof). Out of the “workers,” 71.9% were inactive at least half the time, and 25.1% were never seen working. A small fraction of the ants, just 2.6%, were always active during observation.