I use medicated feed to start, then move to the "start and grow" feed and use that until they start laying. I then move to flock raiser and free feed crushed oyster shell for a calcium supplement. If you were into ALL organic then I don't think you would be asking us this question. The thing with medicated feed is you don't want that in the eggs you eat. If you switch over to a non-medicated feed before they are actually laying then there is time for that to get out of thier system. We give human babies medication and preventatives to keep them healthy, why not our chickens? Used in moderation I can hardly see it being a problem.