even though for now you are the only poster, this really helped me.Make sure there is a fresh cuttlebone in her cage, and try to feed her foods which are high in calcium. Sources of calcium include fresh dark green, leafy vegetables, kale, cilantro, beet greens, turnip greens, bok choy, endive, chard, collard greens, parsley, mustard greens, watercress, romaine lettuce, broccoli.
Also, put a dish on the bottom of the cage for them with water in it.
Are you going to pull them out for hand feeding? if so, you'll need a brooder and you can get formula at a pet store, just ask them for some hand feeding formula for baby cockatiels.
Weaning: You can start providing the babies with moistened weaning pellets and a variety of other foods at this age. Weaning pellets are made just for a cockatiel chick(s). Other foods to offer include cooked brown rice and pasta, fresh, whole wheat toast, cooked oatmeal, bird bread, well cooked scrambled eggs, cooked sweet potatoes and cooked beans, dark green, leafy vegetables: kale, romaine lettuce, spinach, parsley, freshly grown sprouts, corn, peas, carrots, broccoli, green or red peppers, and moistened seeds in food dishes on the floor.
If your babies are reluctant to eat fresh vegetables, try serving them lightly steamed so they are a little softer. Fruits and vegetables contain a high volume of water, 80-90%. They should be served sparingly with baby birds so chicks do not fill up on low calorie foods when they need more concentrated foods. Do not leave fresh food inside of the cage for more than an hour. If babies are reluctant to eat the weaning foods, you can add a small amount of warm, hand feeding formula on top of them and try feeding them moistened pellets by hand.
Weigh the babies daily to make sure they are getting enough nutrition and are not losing weight. Chicks that are in the weaning process still need supplemental hand feedings or parent feedings. If a baby is crying and begging for food, hand feed it. A crying baby is a hungry baby. Babies will start rejecting the formula on their own when they are almost weaned. This is called abundance weaning. Cockatiels that are allowed to wean at their own pace are usually fully weaned by 10 weeks of age. Some babies can take up to 12 weeks. To be fully weaned, a baby must be eating entirely on its own for 2 weeks.
Avoid forced weaning by depriving the chicks of food. Chicks that are forced to wean by 7 weeks of age will regress and revert back to begging for food, neck pumping while making a static sound. New bird owners will not recognize this a a sign of hunger and a need for food. When your chick starts to reject formula from hand feedings, you will know that the weaning process is almost over. It's normal for chicks that are almost weaned to regurgitate a small amount of food after being hand feed. This means that the crop is shrinking, which is also normal.
Hope this helps.