Shieldsey - Does mom have a house to hide in? If she doesn't, you might want to get her one that she can hide in with the kits. Also, you can put in a low shelf, provided there's room on it for her and the kits. You just don't want to put it so high they can't get to her. 3-4 inches off the bottom of the cages is fine and it may calm her down. All these changes are probably freaking her out a bit.