My fiancé and I just got new pet rats the first of this month. We bought them from Petsmart initially we got four (they were all in the same cage) but recently had to send two back. Now we are noticing one of our rats Houdini is sneezing a lot but there are no signs of illness. I've had rats before and never encountered this should we be concerned? Could this be due to the other two going back? Also our boys seem to have a thing for nibbling, licking and wrestling with fingers and toes none of my past rats did this should we be worried about biting? What does it mean?