My dd gave me three gerbils for Mother's Day. It was the most fantastic present. About 2 weeks ago, one started to have shaky, cold interludes .. We looked after him, gave him water with an eye dropper, fed him by hand, he rallied a couple of times and died about a week later.
Now the second one, fine and lively at mid day, had 'droopy eyes' according to dd at tea time, is now comatose ... Obviously dying ... 
We have lots of animals: cats, dogs, guineas, rabbits, fish, chickens, chicks; I think I am quite an experienced pet owner ... I have tried my best to look after them; lots of hay/paper to tunnel in, the food mixture they came with, water bottle frequently refilled ... What is going on?? I really love them ...