[quote=isla49]The rest of your post I agree with. But I don't think it so much a matter of relation but of age. It is likely that when pups were placed with unrelated dogs there was a significant age difference which would lead to that conclusion. I have two unrelated (different breeds) pups here right now with a two week age difference. I had to separate them completely because the younger was going downhill fast. There is a marked improvement a few days after separation.[/quote] Well, we do agree which is why I said dogs instead of puppies... :wink: Sorry, I should have been clearer about that, but I was tired. Though two pups unrelated raised together will usually produce the same result, it isn't quite as intense as littermates (so the studies say). I happen to agree with your observations. Earlier you made a comment about socialization and serving its purpose (in relation to guardian dogs being "over" socialized and not guarding vs. "under" socialized and possibly aggressive). Do believe that intense socialization will ruin a guardian dog? I treat socialization similar to the way guide dog rearers do, intense and very complete, but I demand quite a lot out of my dogs. I also believe that a great amount of socialization helps a guardian make a proper choice when necessary.