Black Bits

The pups are just all gorgeous!  Poor little Button though bless him - where's his share of the black bits??  Little sweetheart!  It's difficult to tell from the picture but he seems to have shadows - will they develop?  How does the colouring thing work again?  I know there has been some discussion on here before but I can't remember what the general consensus was.  

Just a comment on the spaying - our flatcoated retriever had some incontinence issues before spaying but being spayed did make things worse - it was an emergency op though which may have made a difference.  Propalin was very effective.