mice sniffing each other

Question
my mouse had babies and i have decided to keep two of the female babies so the mom has company. i just recently decided on two, i had already chosen one i was going to keep and i separated the rest from them because they can now mate with each other. they have been separated for 2 days and when i decided i was going to keep another baby i put her in the cage with her mom and her sister but both of the mice started chasing after her smelling her butt. is this normal behavior? and what possible reasons could they have for doing it?

Answer
Dear Sara,

it's perfectly normal that they are sniffing each other.  There might even be a little squabble or two.  Since they have been separated, they smell a little different and they have to get to know each other again. No worries!

squeaks n giggles

Natasha