Death of family of Zebra Finches

Question
My husband bought a pair of zebra finches from a breeder and they had 2 chicks , unfortunatley came home today to find all of them dead at the bottom of the cage, yet only a few hours before my husband had been home and said they were all fine. they were all very active and 'chatty' so it was a bit of a shock, any ideas what might have caused their death, we have gas central heating, could it be carbon monoxide poisoning? it seems strange they all died at the same time.

Answer
It's hard to say what killed them. When did they hatch? Babies can last up to four days without being fed but after that they need to be feed often. The problem I find is that a lot of zebra parents don't care for their young.
Other than that, I'm not sure. Babies are easy to kill. Sometimes they get sick and you don't know it until it's too late