OK, I went out and inspected the bird. It has a small sore at what I would call it's elbow, under it's wing. You can see the darker area where the sore is. Evidently someone found her wounded and doctored her unknown to me. I have no idea how long she was gone but I am glad she is back. This makes sense as I only noticed the blue wing two days ago,but, I don't always see every bird every day though.
Sorry for the confusion.
Lots of people use Blu-Kote (Gentian Violet) to treat wounds .. it ends up making purple "designs" like that. It's actually pretty effective but definitely leaves a lot of purple/violet colored feathers just like using povidone iodine leaves brownish/orange feathers.
I was going to say. . .hey, that looks like Blu-Kote! That was nice of someone to treat your bird. It'll wear off over time, and until then enjoy the splash of color amongst the other natural colors in your flock. Of course be sure to keep an eye on the wound.