Just out of curiousity, how large is a budgies crop? How much liquid/food can they hold in it?

Chicks crops start out being able to only hold a few drops of liquid but soon expand enormously. If you put your thumb and forefinger together to form an "0" the crops at their largest get to about that size and very tight/round. After fledging age and onwards their crops shrink down a bit as adults tend to eat more frequently, but less at a single time. Once they are adults they eat a maintenance diet rather than a growth based diet so there isnt the need for such a large crop. During breeding the hens crop gets noticeably large when feeding a lot of chicks and/or receiving feed from the cock as well.

Cool! So when hand-feeding a chick, what would be the approximate amount to give them? At about fledgling age?