I've used nonmedicated for my last 3 hatches and they have been fine. My first hatch caught coccidia when they were about 7 weeks old, and I lost 1 to it, but was able to save the others. The next 3 hatches were far more successful. I learned that if you add dirt to their brooder (like just the dirt from your backyard, preferably from the area they will be in when they are put outside) it will help build their immunity. What I do is
1) Don't sterilize the brooder. Don't put them in a maggoty hole outside or anything, just a quick wipe down and ta-da, be done.
2) Feed them yogurt and other foods with probiotics in them. Coccidiosis is an intestinal parasite, so probiotics will help build good intestinal flora and will help prevent coccidia naturally.
3) Add dirt from the coop, or backyard to their brooder, starting with a small-ish amount, and steadily increasing. It's not rocket science. It's really easy. It doesn't take hardly any extra time, either.
I have raised probably around 50 chicks this way, some from a hatchery, some hatched myself, without incident. I will be placing another order from Ideal in the next couple weeks and will be raising them without medication as well. (If nothing tragic happens of course.)
My goal in raising all my food animals is to use as little medication as possible. I know for some people that's not a big deal, but I really prefer it that way. I hope after I've been doing it for a couple years I'll have better, more detailed, advice. But it really doesn't take much explaining. It's very simple to do.