I apologize for not responding to your post earlier. I don't understand it, but I only just now received notification of your post.
How is your hen? I pray she's well. Whenever my hens first display the same symptoms, I first give them a 15-20 minute bath in the kitchen sink with 1/4 Epsom salts and 1-2 drops of Frankincense.
I then diffuse Oregano directly by the cage that I keep them in for recovery.
If they'll drink it, I also put a bit of raw, organic apple cider vinegar in their drinking water.
Depending on other issues, I will also put a drop of Melaleuca Alternifolia (Tea Tree) on a cotton swab and rub it over their comb and legs for further immune boosting properties.
9 times out of 10, these steps brings a complete turn around. Very plainly, just like with us, giving their bodies support through oils, helps them fight off what's come against their bodies.
I hope all is well.