If you currently have a C&C cage, you will need to baby proof it (so that the pigs can't squeeze through the grids) by either:
1. changing grids from th 1.5 inch holes to the "child" ones that have tiny grid openings or mesh grids.
2. Overlapping 2 grids so that the openings are 1/2 their original size (securing them with zip ties; I believe Ly has a picture of how to do this in her gallery).
3. Raising the sides of your coroplast bin so that the grid openings are covered. You can use either extra coroplast or cardboard for this purpose.
Also, babies under 4-6 monts old require alfalfa hay over timothy. You will need to make sure that they are generally healthy, eating, and are getting their daily veggies, pellets, water, and unlimited hay. Other than that, I'm not sure since I've never had babies myself.
Good luck!
edit: Ack! Piglet answered before I hit "post reply". Always beating me to the chase, haha.