If the medication in your starter is Amprolium, it is safe to eat the eggs if your hens do eat the starter. Amprolium is a thiamine blocker.
All that being said, I never use medicated feed, and I have never had coccidiosis in any of my chicks. The feed store statement about "protecting your chicks" is nothing more than fear mongering from an uninformed employee. When I started my first flock "this time around" (I've had poultry off and on for the past 50 years) I told the employee that I wanted unmedicated chick feed. The reply: "You can't do that. Chicks must have medicated feed." My response: "I'll take my chances, please give me unmedicated chick starter." Miffed store employee: "If you use unmedicated feed, they will die. Besides, we don't have any." Me: "Thank you, I'll be doing business with your competitor." Next year, lo and behold, that store was now stocking unmedicated chick starter. Amazingly, they were now selling the very thing that is presumably the cause of death of chicks everywhere!
I choose to go the natural route regarding building immunity for a strong flock. But, I do not use organic feed. I give my chicks a plug of sod from untreated lawn starting the first week after hatch. I ferment feed for all of my birds. And I use deep litter in coop and run. All of these measures work together to load the bird's gut with beneficial bacteria and fungi to boost digestion and immunity.

