The crew would have been aware of the dog if they were onboard. I know when we are delayed with animals in the hold I try to make sure it remains open if possible. Passengers I find always ask about their pets wellbeing and it doesn't hurt to go for a walk downstairs to check. A delay of 5 hours though? I doubt the tech crew would have been anywhere near the aircraft so I don't think they could be to blame. The loaders downstairs though can't hang around... Maybe a bit of lack of communication between the groundies??