Nutrition does not change drastically, other than the fact that the females appetite might increase.

Pellets – make sure you are feeding a high quality pellet, I recommend Mazuri, an alfalfa based pellet. I free feed all my chins, including pregnant females as well.

Hay – fresh hay is vital to a chinchillas health, and should be provided at all times. If you are feeding an alfalfa based pellet, you should feed a timothy hay. If you are feeding a timothy based pellet, feed an alfalfa hay.

Water - You should always provide freshwater for your chins, and after mom delivers I recommend providing a second water bottle with a 50/50 mixture of water with 100% Apple Juice or 100% Cranberry juice, as it will help moms milk to come in by encouraging her to consume more liquids. Remember, you should provide TWO water bottles, one of plain water and one of the mixture.

Supplement for Mom - While mom is pregnant, its okay to supplement her for the first month or so, but stop soon after because you do not want kits to grow to large to pass through the pelvic space. The next time you can supplement is the first week or so after she litters to help her recover from the pregnancy and to give her strength to take care of the kits.

Supplement for Kits – If mom does not produce enough milk, or kits fight in a large litter, or whatever the reason, sometimes you have to supplement kits.

I recommend using this formula:

1 can goats milk
1 can water
1 tablespoon dry rice baby cereal
1 tablespoon plain active culture yogurt
2 drops of light Karo syrup 

All of this can be found at the grocery store or wal-mart. For information on hand feeding kits, please visit the supplementing section.