They were fine half an hour ago and now are dropping dead. Symptoms are panting, drooped wings, chirping loudly, going limp and then passing. I've lost 3 in the last 10 mins with 2 following. They're between 2 and 3 days old, were on play sand until they started eating it and are now on paper towels. What happened??? Is there anything I can do to save the others!??