Does any of the poopie have blood in it? Do any of the chicks act sick - lethargic or huddled under the light like they're cold?
"The most easily recognized clinical sign of severe cecal coccidiosis is the presence of bloody droppings. Dehydration may accompany cecal coccidiosis. Coccidiosis caused by E. tenella first becomes noticeable at about three days after infection. Chickens droop, stop feeding, huddle together and by the fourth day blood begins to appear in the droppings. The greatest amount of blood appears by day five or six and by the eighth or ninth day the bird is either dead or on the way to recovery."
I had a couple of chicks die from this a couple months ago before I realized what it was, and by then they were just huddling under the lamp looking cold. I think it had progressed too far by the time I finally medicated them. I treated the rest with Corid, and they are all fine. I sure hope yours don't have it, but if you treat them before they get bad, they should be ok. Good luck - I know how you can get so attached to them so quickly!