Color change in Sandboa

I purchased some Saharan sandboas from Dave and Tracy several years ago. A couple of years ago one of the normally colored females started loosing the orange color which was being replaced with white. The brown has stayed the same. Today the white is taking over more and more scales, mostly in the head and neck area looking very much like a pied Ball python. I'm not sure what is causing this condition but it has been interesting to watch. I am posting a picture of her with a normal colored female. Thanks for looking and I would like to hear if anyone has any ideas what might be going on. Jud McClanahan

Jud McClanahan -