You could add some vitamins to their water and provide scrambled eggs.
Inspect her closely for mites and lice.
Deworm her and the others as well.
Did you inspect your coop for poultry mites? It's the time of the year...
Did you inspect her cloaca or did you just cut the poop that stuck in her feathers?
Maybe her cloaca is blocked by poop and needs a careful cleaning with lukewarm water. Be sure to dry her well when done. Usually they poop shortly after being washed, so be prepared...