Hey, I wondered if you were still around. IDK if it's the same type of thing but Ruby's blue area was an almost silver once her adult coat came in. I've noticed the roots are now blacker than they used to appear. Maybe Thor's dark patch will lighten as it grows out?
This is totally OT, but why I had thought of you recently. Remember the Temple Grandin book you gave me in the GE? HBO is releasing a movie about her. I thought you might be interested. Loved the book, btw!
Temple Grandin (2010) (TV)