Finches and Budgies will do 1 - 4 batches in a normal season. This varies due to
1. fertility - if they don;t hatch go again.
2. loss of chicks - if they all die or get killed go again.
3. good or bad season - sneak more into a good season
I was more curious if you had ever noticed an Emu pair do the cock vanishes, reappears without chicks, vanishes again, reappears with chicks thing.