I was playing with Reo's ears today and noticed a green tatoo in his right ear of the number 10. Just curious if this is a normal breeder marking system for their pups? And if there is a way to tell who the breeder is?
I should add that some reputable breeders tattoo as well however they use a unique code of usually two letters and several digits that can be registered and traced just like a microchip. Since yours is just two digits its more likely just a way to keep track of each dog within a litter.
Was he a rescue or adopted as an older puppy or an older dog? It's just not trackable for a tattoo w/ only 2 digits. The reputable breeders that tattoo their dogs will register their tats with a registry.. and you would want to use more than just the number '10' in that case. I have heard of ear tattoos being used as well, but in dogs with more 'ear' to spare, not Boxers.
Unless your dog is a potential breeding dog or show dog, it doesn't matter though, does it? He obviously has a good home now, and that's all that matters. I am guessing the tattoo '10' was given as a means to track a dog that was one of many, many, many dogs. I can't see any other reason to tattoo a puppy or dog in that way (with an un-registrable number basically in an odd place).