Several weeks ago my husband bought my son 2 supposedly female Zebra finches, who then laid 6 eggs and finally hatched 1 baby the weekend of my daughter's 12th birthday. Sadly, the baby died 2 days later as mum & dad had kicked it out of the nest (first time parents) as this was their first breeding this can happen from time to time.
This was a learning curve for my son & husband to stop spying on them every 5 minutes. The supposedly 2 females have now laid again. I have been advised that Zebra finches breed worse than rabbits and can nest anywhere, including the seed container.