Buttermilk coats intestinal lining protecting it from damage by coccidiosis until amprolium, or a sulfa drug or toltrazuril can be administered.
It is also an outstanding probiotic. The boiled rice looks like maggots to chickens and they scoff it up. I recommend buttermilk mixed with boiled...
It would be best to worm her and all your other birds. The worms are sucking the life out of your hen.
Give her Valbazen, 1/2ml orally using a syringe without needle. Then repeat again in 10 days. Same for your other birds.
Then give them plain boiled rice mixed with buttermilk for a couple of...