Hi Ashiah,
All you can do is hope the parents start caring for the chicks again. There may be something wrong with the chicks, or the parents may have made a mistake such as over feeding them. If you try to hand feed them at this age, they will most likely die anyway. It’s hard to watch chicks die from lack of care from the parents, but the parents have to learn, and often this is at the cost of the first chicks. Whether the chicks survive or not, you need to remove the nest box as soon as they leave it, or if they don’t make it, as soon as there are no longer chicks or eggs left. Rest the pair for 6 months, and then let them try again. Most pairs fail the first time, but get things right by the 2nd or 3rd clutch. But the 6 months rest is very important between each clutch.
Thank you for asking Lafeber,
Brenda