x2 when my hens look depressed from worms and I medicate them they spring back within a couple of days I would say. But if terribly sick from it the process may be longer. They can so easily die from worms.
Don't forget to retreat at 10 days, at least that is what I do - to break the life...
https://www.backyardchickens.com/t/420979/vet-treatment-for-sour-crop-crop-stasis
You may want to search for poultry crop stasis, sour crop and impacted crop. I have no experience with those (if that is what your chicken's problem is) and cannot offer assistance on that. I hope she gets better...
https://www.backyardchickens.com/t/948204/watery-white-poo-picture-3-year-old-polish-hen-lethargic-droopy-wings
See post # 2 for what I personally would do - Eggcessive wrote that post.
I know you don't have the drooping wings issue with your hen but my first thought was to try a different...