Sick Hairless Rat

Question
Last night I went to let my rats out to play and roam like I do every evening and my hairless dumbo didnt come out of the cage.  Usually I just open the door and they come running out.  Shes usually the more active one who is too busy running around to be held.  I picked her  up out of her house and she wouldnt move.  Her sides were sunken in, her back was hunched up and she was very cold to the touch whereas usually shes warmer then the other rat.  I wrapped her in a blanket and fed her little pieces of lettuce which she ate very slowly.  She laid in the blanket for about an hour until she was warmed up then started to walk around a little bit and picking at some more food and drinking some water. (Normally she never holds still at all)  I myself get cold easily so the house is always warm and shes has an igloo house in her cage to keep warm in as well since shes hairless.  This morning she was moving around more and no longer looks all sunken in and hunched up.  She also feels like shes at her normal temperature. Shes still not acting as hyper as usual but way better then when I took her out last night.  Do you know what couldve possibly caused the problem or made her sick?  Should I still take her to a vet?  The other rat that shares the cage is perfectly fine but I cleaned out the cage and changed all the food, water, and bedding just incase something in there made her sick.  

Answer
Since rats are delicate little pets I would still definitely have her seen. How old is she? If she is reaching old age there is a chance she may be slowing down a bit. Though an igloo is a great place to hide in, it is not sufficient for keeping her warm. Invest in some heavy duty fleece blankets or hammocks for her to curl up in during the winter months. :) Has she had any sneezing? Any other signs of illness since this episode?