3 weeks old, in large brooder( converted Great Pyreness dog crate), with about 35 other chicks of various breeds. It is a bit on the small side, but all my birds appear in great health and have been thriving. Last night I found it laying on it's back under the light in the brooder. The other birds were not harassing it, but I am greatly concerned. I isolated it in a separate, smaller brooder with 8 other welsummers, positioned it in a corner so it would at least be protected on three sides. It seems to have an issue with it's right leg, but could limp around to get water and food. However this morning, it was on its back again, sleeping. I think it's some sort of trauma, though other than the limp I can see no obvious source of injury. The birds have had no access to treats or anything I believe would be toxic, but the fact it wants to lay on it's back is very puzzling. If this is indicative of something neurological and a threat to my other birds, please let me know! Currently, I don't know what to do other than let it expire.