Just curious, why put a unknown chin into your herd when you can just as easy get one that is known, its not like there is a shortage of chins.
Actually... there is not a shortage of chins, but it can be hard to find chins with specific traits, violets for example, it's hard to find really nice violets anymore, they're all dark and muddy or ratty looking.
To me this is not a chin without a pedigree. If you have a specific date, I find it hard to believe that someone would have 12 violets born on ONE day. Since the person you got them from got the chin directly from the breeder doesn't the breeder have a record that they sold that chin to that person?
Dogs have advantage over chins as far as pedigrees and genetic issues. Firstly dogs don't have a disease that really compares to malo. Malo can carry for generations before showing up. Dogs can all have their hips and eyes certified by the age of 18 months, actually I believe both can be done before the age of 12 months or sooner depending on the breed, chins can't be certified "malo free" at all, let alone at a younger age.
Let's say malo, unless you have a large number of animals, or know others who do, with that same lineage it's impossible to tell if malo is genetic from a pedigree and not environmental.
To the OP, did the owner have any kits born from this animal before? Perhaps someone she sold a kit to would have a copy of her pedigree from their animal's pedigree or at least her number. Again out of 12 animals born on a day I can't believe that all of them are violet, which makes me question the record keeping there. Depending on the number of animals total and how many of them are violets/carriers... I still think it would be very odd to have many violets born on the exact same day without having 1000's of animals.