I raised one batch of chicks organically (on unmedicated chick starter), and am working on my second. I found some tips on BYC for slowly exposing the chicks to the coccidia in the soil so they wouldn't get overwhelmed when I finally put them outside. As mentioned by Michael Apple, at week 2 or so I start putting a handful of soil into the brooder with the chicks. Then I'll slowly add more, I'll give them a clump of sod so they can dig it up and tear up the grass. The advice I've seen is to get the chicks outside as soon as possible, but my coop wasn't read with my first batch of chicks until they were 5-6 weeks old, so we built a pen outside that I could put them in for a few hours at a time. My problem now is that I'll be adding chicks to my existing flock, and I'm worried about the chicks getting sick from the big girls.
Everyone told me I was crazy for not using medicated feed, but my chicks were fine. I've read that chicks raised in cooler weather will be much less likely to develop coccidiosis than those raised in warm weather. I do own Corid, which I'll use if I need to, but I hope it won't be necessary.
If you're not raising your chickens organically and you're worried about coccidiosis, you might want to use medicated feed so you have one less thing to worry about. But even on medicated feed chicks can get coccidiosis, so I'd either get them outside as soon as you can or start adding dirt to their brooder to get them accustomed to the coccidia in your soil.
