Today found 3 babies dead on cage bottom....

Is this normal?

I am new to finches (pair oz Zeb's)
do you think the other two babies will make it?
Mom is in the nest alot. Cant really tell if they are feeding them. The parents both eat well, so I assumed the babies were being fed?
What do you all think I should or could have done...
I am feeding a mixed seed, millet eggfood with small amount of baby rice cereal in it and a few mixed veggies... and dried egg from pet store in the mixture too.
Thanks,
