Budgie Not Laying In The Nest

Help

My son is trying to get started. We bought a breeding pair who had eggs, but the eggs were never hatched. Its been about three months and now they are showing the breeding signs. The past few days we have gone out to do their food and water and there have been eggs on the floor of the avairy. Its like she is not even trying to lay them in the box. Why would this be?

Any help much appreciated