This is heart-breaking & very perplexing. Were there any marks on the babies? It would be very unlikely that both parents would just disappear & abandon the babies for no reason. Is it possible that someone did some spraying in your area & maybe the babies got a dose & they died from that? Maybe the parents knew there was something wrong with them. I do know that something similar happened to be 9 years ago, when one day the 5 babies were perfectly okay, & the next day they were all dead. Parents did not abandon them, but only logical thing we could come up here is insect/herbicide spraying. There were no marks on my babies. I could understand 1 or 2 dying but when all perish, it is hard to figure it out. So sorry. Someone else – chime in here.