I have pedigree Lab Dogs pair consisting of Male Black and Female Yellow Colour. On April 27,2015 the 1st litter was delivered. The total litter was 7 pups (5M & 2F) out of which 4males died in 1st couple of days. The surviving dogs and thus One Male and Two Females.
All the three pups are black. However the male pup has brownish patches on lower portion of legs. Similarly one of the female pup has a small white patche on back under the tail. I am sure that external crossing is not possible. I have been told that this is a sort of fault of pedigree and the litter is not a pure breed. Is this true? Please let me know the factual position.