If you are using a medicated food with Amprolium in it (which is a coccidiostat, so it doesn't kill coccidia it just slows the growth so the birds can build a natural immunity to it), then stopping now is a bad idea.  Coccidia take 1-2 weeks to complete their lifecycle and start causing problems in the birds, and they'll be exposed to coccidia as soon as they have access to dirt.  You want them to have the medicated food until at least 6 weeks old, and longer if they are housed indoors early on.
I know I have coccidia at my house because my dogs eat the chicken poop and then test positive for coccidia (doesn't make them sick because all coccidia are species specific).  But chances are you have bird coccidia too.  My chicks are outside by week 2, so they stay on medicated food until sometime after 6 weeks when the bag of food runs out.