Some of the people around here who breed hunting dogs use a tattoo to help them identify their dogs for breeding purposes. I don’t know if they would do that with labs, these are hound dogs.
Tattoo could be breeder number, National Dog Registry number… there are quite a few possibilities. NDR is the largest databse, you can also contact the AKC. Most rescues should be trying to track down any info on a tattooed dog.
