I am strongly in favor of feeding medicated chick starter, especially given our moist, hot enviroment here in SW Arkansas. I fed it to my last batch of chicks right up until the first egg (there was no seperate grower available around here then) and never had a problem with coccidiosis. Today we went to town to buy chick starter for my 4 1/2 week old chicks and not a bag of medicated starter to be found in a 50 mile radius. The manager at the co-op told me they are having trouble getting starter right now. I ended up getting some 17% grower, unmedicated. Is 4 weeks on the medicated enough to be effective to build a coccidia immunity do you think? Most of the chicks are now on the ground for at least a little while every day, while others aren't yet venturing out.