So, I'm pretty new to chickens. Here is how everything went. I bought 16 golden comet chicks about a week old and started them on medicated starter and have kept them in the brooder since as our larger coop is not yet ready. They have since been moved to an even larger brooder to accommodate for their size. In the mean time, I bought 8 bantams that were about 5 months old or older, to train my LGD's with, as they are puppies. I have had 6 of those carried off by eagles or eaten by dogs. I also acquired 5 silkies (2 older, 3 younger). When I first brought them home, I had them all in the smaller brooder that my golden comets had been in until I moved them outside a few days later (it was really cold!). The other day, one of the small silkies was lifeless, but still alive in the coop when I went out there in the morning. I brought it in, and thought it had nearly frozen to death because it was a very cold night. It died a few hours later. The very next day, the other small silkie was perfectly fine (seemingly), then an hour later, it too, was found limp just laying on the ground. Because my bantam rooster was so much bigger than the silkies, I thought his aggression had broken their necks. Then this morning (in the same brooder that my golden comet chicks originally were in, and the silkies were in), I found my pair of bielfelders (about 5 weeks old) dead! The more I think about it, the more the signs were there, but I didn't notice them. Last night the roo was puffed up and the hen was cuddled up under him. I thought they were just cold. But I also noted how much calmer they were with me petting them and so on. I think that the 4 of them died of cocci, because upon closer inspection, I think there is bloody stool in the brooder with the bielfelders. My concern is for the 20 other week old or younger chicks I have in another brooder as well as my golden comets and other outside chickens. Can I give them the medicated chick starter and they'll be ok, or should I do more? Also, what do I do with the brooder that I think is infected? How do I get it clean? There's still the third silkie outside with my two original bantams and two older silkies. The 4 older of the outside birds seem fine. Is feeding the medicated chick starter while they're young the best I can do to prevent it for my other chicks? I'm worried about the ground outside and the coop where the two small silkies were, being infected. Any thoughts or words of wisdom would be appreciated. I'm still not entirely sure where it came from. Either the silkies brought it with them, then infected my brooder, or my brooder was infected from my golden comets, which all seem to be fine. Thank you!