My Zebra Finches puffed their feathers, what does that mean?

I got two female Zebra Finches for Christmas. They were healthy and skinny. Next day they both puffed their feathers up and stayed that way. About 5 days later, one died. The other one stopped puffing its feathers when we pulled the dead bird out of the cage. The one bird that has died we can not tell what of. No scratch marks or anything. Seemed healthy Christmas Day. Thanks for any help.

(I'm worried about the other one and the new friend I'll be getting it as one alone is not happy or so my book said.)

~John

EDIT: Please note that by skinny I mean regular size.

 

Hi Sorry to hear about one of you zebras dying.
Sitting with fluffed up feathers is usually the first sign of illness.
Birds that have something wrong but look fine will show being sick with stress like new surroundings, stress of travel.

I would have taken the dead bird to an avian vet to have them do an autopsy to see what caused its death and to see if the other is at risk.

When you get a new bird it needs to be kept in a seperate cage for 30days away from the other bird this will give time for any illnesses it may have to show itself.

Other signs of illness are not eating and drinking, sitting usually either in the nest or on the cage floor all fluffed up and look like they are really sleepy.

If your worried about the other bird i would contact and avian vet and let them know what has happened and see if they will check your little bird.
Zebra finches are very delicate birds and the slightest thing can stress them

Zebra finches are flock animals and prefer to be kept either in pairs or a flock off them, if having more than 2 always make sure you have more females than males or you will have serious fights...

Mike