Birds can pig out and get a really big crop, however it could be a problem with her crop. A bird's crop is like a bag that holds the food they eat. It is held there and moistened and gradually fed into the next stage of the digestive process. Normally the crop is full in the early evening when the bird goes to roost and it empties overnight while the bird is sleeping. If you check a crop early in the morning before the bird eats again it should be empty or almost empty.
If there's a problem I would guess that your bird either has an impacted crop, or otherwise a pendulous crop. I would feel over her and see if she's skinny and losing weight or if she is well covered. Also feel the crop and describe what it's like. People on here will no doubt be able to head you in the right direction.
An impaction is when the food gets matted up and forms a lump in there that won't break down and pass. Long grass strands can start this off, but sometimes it just happens. The first thing that I would try with an impacted crop is giving the boil some olive oil, leave it for ten minutes, then firmly but gently massage the crop and see if the mass breaks up a bit. You can do that a few times a day to see if the impaction will break down. In extreme circumstances you can do a crop surgery to remove it, but people lose as many birds as they save. I would always try massage and oil first. I would also stop the bird eating long grass or hard grains while trying this. I would give soft foods and I would also put vitamins in the water as the bird may not be well nourished.
The second possibility is pendulous crop. That is where the crop is actually stretched and saggy. This means that food catches and balls up in the lower part and doesn't ever move through. These can't be cured although people try things like surgery or even a 'crop bra'. Surgeries don't tend to work as once a crop is saggy it tends to go back like that even after a surgery. I've never tried a crop bra, so go for it if you feel like it, but I don't really have a lot of faith in it. When I've had pendulous crop cases here I've found that they can hang on for quite a long time living normally. Usually the day comes eventually when their health is compromised and they don't tend to be long lived.
If the crop goes down to a normal size overnight then you know she was just a pig.
