Our Bella seems to have thinning fur and its usual black color is turning brown. Could this be do to the harsh dry winter air or do you think something else could be going on?
tris and blacks will sometimes change colors as the undercoat fluffs out. Greyish. Or sometimes with tris there will be some bleeding between the brown and the black during the shed.
I noticed that Daisy (a tri) is also having lighter colors streaked through parts of the black on her back and sides. This is her first whole year in life so this phenomenon is new to me too. Duke's black and white doesn't change, but I notice his shed is usually white.
That picture looks exactly like our Ella. My wife has been saying the last several days how "gingery" her back has been getting. And a month or so ago the area behind her ears became extremely light colored.