Just from eating normally.
Excellent news about her crop functioning properly! A crop isn't exactly like a stomach, it doesn't actually process the food... think of it like a holding tank that will empty contents into the digestive tract as needed. Birds don't seem to realize when their crop is full, they seemingly just keep stuffing it as long as there's goodies to stuff it with. It's important to note that some of that volume is water, and the hotter it is, the more water they drink, the bigger their crop gets :d Also note, that as we come into the heat of the year, that all that water will make for looser stools that make their poop look to be diarrhea... and there will be a lot of white coloring in their poop along with whatever other coloring is going on with their excrement at the time (green, brown, and deep dark mud among other normal colors)... that white stuff is the urates (bird pee), and absolutely nothing to be worried about.
