Since it is summer where you live,,, close the door,, and install a fan into the window. Fresh air is best medicine.
Reason I say close door,,,,,, since the rest of the house may be airconditioned,, you only want to remove air from that room,, not whole house of COOL air.
WISHING YOU...
Unless you can keep that hen isolated indefinitely, removing would be best option.
I had a similar situation with one of my hens. She scalped one of my seramas. Really bad:hit
I relocated her to a neighbor that keeps only large chickens.
Now,,, I only have bantams.
In previous times, I...
They most certainly are. If you look closer,, you can see small fish swimming around that coral.
I'm not certain,,,, but think this is an Aquarium Display
Your chicken may not have a problem at all. Generally broody hens seem to molt feathers on their underside to incubate eggs. This way they transfer warmth to eggs easier.
Lets see what others think???
Mites,, Lice,, you can usually see them lil devlz crawling around :frow
WISHING YOU...
I don't know anything about duck eggs, or misting them.
But do have an opinion about your temperatures. I don't think ½degree Celsius difference rang is significant. Your incubator thermometer is not laboratory grade instrument, so you actually can be off,, up or down. Eggs still hatch...