There is grass in the budgerigar's nest. Why did they take it out again?

This is the normal performance of budgerigar. Before laying eggs, the padding basically came out, and the shavings I padded basically came out. Don't worry about filling them now. You can wait until they hatch, even after the birds hatch.

The padding of budgerigar should be mainly shavings. Hay, a small amount is no problem.