I'm so sorry to hear that she is without the babies and not wanting to go outside (if they are out there). I wonder if you could wander around out there on your own and listen for them. I know it might be hard to hear them with the busy road right there but hopefully you can make out some kind of sounds? Same thing inside your house. Maybe ask everyone to be silent for 10 minutes and walk around the house listening. I know it would be hard with so many kids but tell them how important it is and that they could help in the search for the hidden kitties. I sure hope you find them.