Last Thursday I posted about how one of my silkies died for no reason. Most said that sudden death in chickens sometimes happens. Today, another silkie (this one was broody) just died. No injuries, mites, lice, sickly behavior or anything. It's been kind of cold here (about 20-30 at night) but not very cold. The coop and run are secure, so nothing could have gotten to them. Could this be a disease or are silkies not able to handle cold? It's already Feb 20, so they were able to handle the winter so far, so I find it weird that now the cold would get them. What could be happening?...and are all my other chickens at risk to die now also?