Give her a few drops of warm sugar water. Place one drop after another on the right side of her beak and she will slurp in in. This will elevate her glucose and it may be all that's needed to give her the strength to pull her legs under her.
If that doesn't work after a few hours, try a few drops of vitamin E oil, administered the same way. This may correct a vitamin E deficiency. You may also try dissolving a vitamin B tablet in water and administering this water in the same manner. Vitamin B-2 riboflavin deficiency can cause this, too.