How to distinguish Labrador puppies

How to distinguish a Labrador puppy? First of all, Labrador puppies generally have a small bump on the top of the brain (grow up without it), the mouth should not be long and thin, should be short and thick; ears drooping, lightly pull the ear tips, can touch the other side of the corner of the eye for the best; remove the head and tail part should be in square proportion; hair color only black, yellow (dark yellow, light yellow), chocolate three, other colors are out of order or impure; black Labrador generally all black, individual have The white hair on the chest is out of order, but not impure, the tail should be to the back of the fly section for the best.