rat with cold feet

Question
I just got a rat a week or two ago. she is a dumbo eared rat. today i noticed she
had cold feet and she is a lot more active than she has been the past few days.
she is also all white but i noticed her head was a little differently colored today,
not a big difference but i noticed it. she isn't acting sick. i was just wondering if
cold feet mean.

Answer
Cold feet could mean a few things: lack of oxygen if she is suffering from a respiratory infection or else she is cold. If she is acting ok, she is probably cold. What do you keep the room temp situated on? What do you mean her head is a different color today? The fur has turned colors?  Is it maybe a darker color, perhaps she is a tan hooded rat and her fur is changing as she ages?