To be able to spot a 'good pedigree' it takes a lot of research. You need to know what health problems different lines have. You need to see the dogs produced in 1 line to see what that line 'looks like.' I've been learning about pedigree's from my mentor who's a breeder/show-er. If you're just looking for a pet, pedigree's should only matter to know how big the dogs are in a line and any health problems that line has. I'm sure yorkierose can provide some more insight
