I've seen references to putting an older chick in with newborns a few times, but no details and searching didn't come up with much. I currently have 8 chicks in a brooder, ranging in age from three weeks to almost ten weeks. One of the three week olds is way smaller and quieter than the rest. She does fine with them, but she is so tiny. The other three week old has more feathers and is way bigger than she is. I don't have lights on them anymore (they're in the house), and again, she seems fine with that. Anyway, I'm getting 8-10 newborns later this week. I was going to put them in a cardboard box to start, which is around 3'x1.5'. Hopefully by the time they outgrow that our coop will be done and the others will be out of the big rabbit hutch (which is about 12 square feet) and then the new babies can go in there. When I saw the suggestion on another thread to put a runty older chick in with new babies, I thought that was a wonderful idea. Someone said the older one would show the babies about eating and drinking and I think it might do her good to be the biggest for once. So my questions are: How old should the newborns be before I put the older one in with them? I'm getting all but one or two of them locally, so they will only be a day or two old when I get them. The other two are from someone who is getting chicks from Ideal Hatchery and will be three or four days old when I get them, though after reading threads here about lots of hatchery chicks dying I'm unsure about those two. They are the only source of Chanteclers I've been able to find though. Are there any problems associated with the older one going from a brooder with no lights, to one with a heat lamp on 24/7? Kind of unrelated to the older chick in with newborns, but am I going to have problems integrating the two groups together down the road with a 10-week age gap?