The age of the child is less important as is their development status. If the child is able to stay in the bed without rolling over and out of the side, then it is okay to let them sleep in there.
Gerbil pups should remain with their mothers for at least six weeks, if not eight, even though they are weaned at week four. Gerbils still have many behaviors to learn, and separating them from mom...
I'm not to sure,depends on if you have orpahned mice or mice with it's mother. I am taking care of 1 orphaned baby mouse now. I just set him on paper toweles and a sock to keep him warm. I am just...