My black labrador Hattie has a litter of 4 week old puppies with another black lab, 9 blacks and 2 yellows. About 4 of the black puppies look slightly strange in colour (the smallest 4 for some reason) They look slightly more grey than the other black ones, have light nails and almost brownish paw pads. Some are on different degrees of this to others. I am aware of the possibility of charcoal labs but they do not seem light enough to be charcoals. Has anyone else come across this?