I do think it would be best to give her a bath, it's not as hard as you might think, just be sure to do it someplace where if she splashes it won't matter (we wash chickens in our laundry room.)
Here's an article I've posted on our website about how to wash chickens. If I were you, I might do so with a flea shampoo, just in case she does have mites:
http://pathfindersfarm.com/Washing.html
What you'll need:
Three pails or large buckets
One large towel per bird
Dog nail clippers
Dog nail file
An old toothbrush
An old washcloth or other rag
Blood stop powder, or cayenne powder (in case you nick a quick)
Carriers deeply bedded with clean shavings
Hair dryer (if it's cool outside)
Dish soap or some sort of show shampoo (better to use something like Ivory than Dawn, which strips too much oil from the feathers)
Apple Cider Vinegar (ACV)
Crates deeply bedded with shavings to put the birds into for the final drying time.
Fill the buckets with warm but not too hot water. Put some Apple Cider Vinegar (ACV) into the second bucket
(not too much, just enough to cut the soap) and if you are washing white birds, several drops of bluing into the third.
Gently lower the bird into the first bucket (but do not cover the head), swishing it up and down to get the feathers wet. Put some soap into your hand and gently
brush it onto the bird, stroking in the direction of the feathers, not against the grain.
Work the soap in, paying attention to the vent area and the toes. Be careful with soap around the eyes, best to just use a washcloth to wipe the head area. Use the
toothbrush to scrub the toes and legs, get all the crud off of them.
Transfer the bird to the second bucket, swishing up and down to get the soap off. Then put into the third bucket for a final rinse. Wrap the bird in a towel, leaving the head
and feet sticking out. Sit with it on your lap (you will get wet) and gently trim toes and beak if needed. Use the file on the beak to remove sharp
edges and refine the look. Wipe around eyes again with the towel.
Use the blow dryer with caution, not too hot! Using the warm (not hot) setting on the blow dryer, dry the chicken so that it is almost dry (you won't get it all the way dry.) Place it into the crate with shavings in a warm, non-drafty place to finish drying (this may take several hours.) We find we can do between six to eight birds per day effectively (run out of crates!) Once the bird is
completely dry, return it either to the cage or its clean pen.)
Note:
Before you wash your birds, you should always check them for mites or lice, and treat appropriately. It's no fun trying to wash a bird with mites crawling all over your arms (yuck!)