I have six nine-week-old bantam Cochin chicks, one of which suddenly turned up sick for no known reason and with something I can't identify. I hatched and raised the Cochins with mother hens, one of which decided to wean her four babies on Friday morning. The other mother hen, her two chicks, and the four motherless chicks all went out into our flower garden where they have been staying during the day for the last couple of weeks. The four weaned babies called for their mother a few times, but after that they seemed fine. At night, I put the four chicks together in the carrier that they were used to sleeping in with their mother, and they seemed to settle down pretty well. Saturday morning, since I was home, I decided to let the Cochins out loose with everyone (we free range our adult chickens), as 2 to 3 months is the age I usually introduce young ones to the flock. Lena (the remaining mother) and her chicks mostly hung out on their own or with the other chickens under our lilac bushes. The other four chicks went through the fence into the large vegetable garden, which was the first place they were allowed outside with their mothers (until we planted new plants and their mothers decided to dig them up). That night, I rounded them up and got them into bed per their usual. Everyone seemed fine. Sunday morning (yesterday) I went into the barn to let the chicks out of their carriers. Five of them were normal, but the eldest of the four weaned chicks was not acting right. He didn't want to come out of the carrier, was fluffed up as if he was cold, and was very lethargic. When I picked him up, I noticed his feet were cool and not warm like the rest of his siblings' feet. I set him down with the others and he ate and drank a little bit. I held him on my lap for a while to see if warming him up would actually help, and after a while he got up and wandered around. That afternoon I put them back in the flower garden so they would be in a controlled space. Considering that 1) Cochins are extremely fluffy, feathery birds, 2) The chicks are almost completely feathered out, and 3) The current temperatures here are hot, Hot, and even hotter with lots of sun and humidity, most of the chicks were panting at some point during the day even when hiding in the shade with lots of cool water. The sick cockerel, however, spent the whole day looking slightly fluffed and not doing much. That night, he was much the same as in the morning. I carried him with me while I gathered eggs to keep him warm, and he acted a bit better after that. I saw him eat and drink a little more that evening when I was getting the chicks in bed. When they were out during the day I saw him eliminate a small amount so it would seem his digestive system is at least working. His color is good, so I don't think he's under-oxygenated either. I've tried looking up illnesses in 9 week old chicks, but everything I came up with was pertaining to baby chicks much younger. This morning when I went out to check on the chicks, he was pretty much the same, except perhaps more lathargic. He wasn't interested in food or water either, so I dipped his beak and made him drink a tiny bit. He didn't appreciate the beak dipping and flew off my lap and onto the top of one of the carriers. Good sign...? I'm going to try giving him some goat milk from our goats to see if he will drink that--he drank some yesterday, and often I've had sick chickens that refused food but would still take milk or yogurt. Additional info: The chicks hatched form shipped calico Cochin eggs I got from My Pet Chicken. Everything I've read about issues with shipped eggs talks about the eggs not hatching, or needing special treatment in order to hatch/the chicks may need help hatching. The eggs I got were intrusted to the incubating skills of mother hens, and all of the chicks hatched without my assistance. I don't know if the eggs being shipped could in fact affect the chicks this late in the game, but I thought I should mention it. Also, since calico coloring in Cochins is very new, I don't know if inbreeding for color has caused genetic problems? What I've read on different breeders' sites give me the impression people are being careful to keep some genetic diversity even if it takes longer to get the colors consistent that way, but this could vary from breeder to breeder. Any advice on what could be going on with my cockerel would be greatly appreciated. I've never had chicks get sick at this age before, and certainly never so quickly!