You can say that my hens should dust in the sand pit I made in their run, but they won't. They have taken over one of my raised beds, so now it is just growing chickens and rosemary.
If she were mine, I think I would bring her into an air conditioned room for a day (in her old brooder), give her cold fruit to nibble, and see if it makes a difference in her behavior. I am farther North than you are, but two weeks ago we had a heat wave here, then rain for a week or more, and...
Could it be the heat? My black hen shows more signs of excess heat than my other girls. I also have 6 and am on the West Coast. Personally, I have been napping in the heat of the day and eating less, and those are normal behaviors for the sudden change in the weather we've had lately, so I...