I have a litter of American bulldogs, 2 were born pure white now their 3 weeks old and have changed colour

Do you think it's a merle or blue and white? Mam had a merle grandad.
I have a litter of American bulldogs, 2 were born pure white now their 3 weeks old and have changed colour

Do you think it's a merle or blue and white? Mam had a merle grandad.
