Chickens aren't normally given "medication" for anything - if there's something specific you're treating for, you'd generally only want to treat the bird that needs it, and only after you've confirmed that there's an issue.
I don't do medicated feed as I feed organic from the start, and my chicks are exposed to the flock and outdoor conditions immediately so they can naturally build up some immunity through exposure.
If you have a known/active coccidiosis issue in your set up, then medicated would probably be a safer bet, assuming that the chicks have NOT been vaccinated for it.