My best guess (and that is all it is-with 4 boys I have no "female" keet behavior experience), would be she is trying to nest. As was mentioned, if she is in breeding mode (is her cere dry and crusty?) but NOT with egg, it would actually be good to discourage the nesting behavior with the rocks in the food dish.
That will also create more of a foraging environment for getting the seeds and would be good too.
I have no idea how you tell if she is "with egg" but maybe if you posted that question in the breeding forum? Have you seen any "activity"?
If she is in breeding mode, maybe if you shorten the amout of light she gets would help. Did you happen to switch food? Like Bluebird said maybe she doesn't like the food. What if you use a dif dish in a dif place? IDK, just throwing ideas out there LOL
totally agree with pudgie mom,females will do that when their tying to build a nest.how old is she?my suggestion is to move things around in the cage.when they become too comfortable they will do that and sometimes lay eggs.
when you wish upon a star,you pray you wish comes true.
Sweetgirl does that sometimes, usually if there is any new seed or pellets in the food dishes. She especially likes the sound the expensive pellets make when hitting the bottom of the cage, and they are in dishes too small for her to sit in so it is not that she is trying to nest, just telling me she is displeased with the food selection. She usually stops after a few days. But I put more dishes in the cage with less seed in each and the outside birds are well fed - I throw the seed she has tossed on the bottom of the cage outside on my balcony.
You could also try using silo feeders. A creative big that simply likes to toss food can still do so but most won't. Don't switch all at once though. Add one or two and when you see them eating out of them, then remove the other ones that they are used to.
Personally, I don't use the dishes that came with my cage. They are too big and I don't like them that big.
I don't have any real advice to give you that every one else has already said, but my handful hen Snezana would get up in the food bowl and lye down and eat what was around her, she kicked around a bit but just to get her legs buried in the food. She does it almost every day. Not sure why though. lazy indulgence perhaps? food fetish maybe.