Some chickens seem rather keener on hygiene and grooming than others.

I have a white hen called Dink and it seems everything sticks to her. She does dust bath but she’s super fussy about what she’ll bath in.

Her rooster doesn’t seem to mind.
You could try building a dust bath using dry soil and wood ash and drop a few hints that a bath would make her more attractive.

On a more serious note, check her feathers over for oil coating. Look at the base of the feathers around the follicles and check her preen gland is damp.
If there are traces of oil at the above mentioned points then you’ll know she can condition her feathers properly if she chooses.
Washing chickens in water is completely pointless with regard to the chickens view of cleanliness and hygiene.
https://www.backyardchickens.com/articles/why-chickens-bath-in-dust-and-not-in-water.74441/