I think all the strays (and my dogs) have chocolate fever or something…
There is this fat black dog that lives at our little guard house…and she has gone from black to brown…a reddish brown.
There are 7 new strays that appeared overnight…and they are the same weird color. And my own dogs have changed color too. The texture of my dog’s hair has changed…it’s gone from black to almost a whitish light brown (behind her ears)
I thought it might have been the change of season…but my dogs have done their shedding now and they still look weird.
I had the same thing happen with my cats -black ones, actually, tuxedos- especially their underbelly, and the vet said it was “sunburn”. It went back to normal eventually.
However, you state that yours look weird, as in all brown. I remember looking up in the Internet and not finding any info on mold/bacteria that could cause that kind of discoloration. However, I’ll look again.
I just called the vet and he said that if it is just a change in color, it should be just that they are shedding fur -change of seasons. But he says that you should check the skin under the fur, see if there have been any changes, flakiness, redness, etc…