Urgent help with blue tit nest

Hello, 

I am writing here to seek help regarding blue tit nest we have in our balcony. So we had a bird house nailed on the wall, the blue tit laid eggs and the chicks have hatched. There are 7-8 birds. Yesterday morning the bird house broke and fell on ground. We picked up the nest and kept the chicks inside it. We assembled the bird house and kept it on porch in the balcony, just below where it was originally kept. The parents are visiting the nest but is not entering the house and the chicks are not fed. 

I am unsure if the mother had seen chicks fallen on the ground and is disturbed. Being concerned I thought it would be good to keep the fallen chicks safely back in the nest. Attaching the pictures here for more details. 

Can you please help me on how can I handle the situation? If the mother doesn't attend, is it good to feed birds? And if yes, what can we feed them?