You will get varied opinions on this one! Some folks like medicated feed and think it helps keep them healthier during their baby growth.
Some people won't feed medicated or give medications unless a bird is sick and needs it. Some are going organic and won't feed, or give, any medication at all.
Me? I feed all my birds(even the babies) unmedicated laying mash, or pellets, mixed with crimped oats. No vaccinations, no medications. If they sicken or die (which none have ever done) they weren't fit to be in my flock in the first place. I put a little vinegar in their water the first week or so, then no more. Some people believe that the high calcium content in laying feed will hurt a chick's kidneys, so you have to follow your own heart on that one. I freerange and leave my coop open, so my birds have access to all feeders.
This is my first batch of hatchery chicks. So far very healthy, no pasty butt, no illness or death. Just very big, healthy and active birds running everywhere...bright eyed and bushy...er, feathery tailed!