The RIRs I had did develop a few black tail feathers but then it was easier to tell them apart 

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There are many thousands of Rhode Island White hens, they are the same and of the same breed as the red ones.I never knew there was a Rhode island white . they look similar to leghorns. They dont even look like the reds.
Just found this. It is true! My chickens got attacked by a dog. The two got hurt ( road island red and partridge Plymouth rock) have a single white feather where they lost ones from the dog.Yes, black feathers damaged or plucked out violently can grow back white, or partially white... actually, this can happen in any feather color... and in chickens, ducks, geese, etc...
Some just get whiter as they age as well... Cayuga ducks are well known for going 'white' as they get older...