Ah :/ I'm so sorry. I just lost a little newborn chick in my hand about 10 minutes ago as well. That's why I'm here. Trying to figure out what to do. I'm afraid with my quail that there's a sickness going around and it's taking a toll on the weakest ones, and the chick might have caught it from his mother. Sorry for your loss. I don't know much about disease, but make sure to clean up after her so others aren't exposed and if they start showing any symptoms I'd take them to the vet right away. With my hen, it was the fever that was the biggest threat, and the immediate concern was lowering her temp, so if they seem to be panting, it could be a respiratory infection and you may want to move them some place cooler. It's hard to know when birds are really sick as they try to hide it, but keep an eye on them and if you notice anything else out of the ordinary I'd call the vet.