Baby Mice
The development of baby mice is very interesting to witness. However, one must be sure not to disturb the mother as she may become extremely protective and even eat her young. If the nest is located in some form of nesting box, it is best to resist the temptation to look inside for at least three days after the babies are born. Even though it truly depends on the mouse, I find that my females usually tolerate handling of their babies once they are 3-5 days old. However, you are always taking a risk when you disturb the nest so soon after the birth because the mother's actions can be unpredictable. Here's a chart depicting the average growth of baby mice:
0-3 days
the babies are blind, deaf, and completely hairless
3 days
the pigment of the skin is visible on darker colored mice
5-7 days
days fur begins to grow and ears perk up
10-14 days
eyes open and the babies will become increasingly mobile and begin experimenting
with solid foods
12-24 days
the babies will enter what's called the "flea stage." They are extremely quick and jumpy,
which makes them very difficult to handle
21-28 days
the flea stage comes to an end, and the babies should begin weaning from their mother's milk
28-35 days
males and females should be separated, and the mice are ready to go to new homes