This one isn't for me. A friend got their first dogs, two Alsation puppies from a respectable breeder, and have had some real problems. I'll call the puppies Anne and Bob, not real names to protect owner and breeder's privacy. Anne was fine. She could be left alone in another room, go on walks with out Bob without worrying, and was very, very, calm. Bob wasn't. The only way I can think to describe it was clingy. If he was with Anne he behaved the same way as her, but if he was away from Anne, for example if she walked into another room, or if he was taken on a walk even still in visual distance but not right next to her, he became unmanageable and aggressive. My friend's husband couldn't manage the small puppy when he got in this state. The second he is back with Anne he calms down instantly. Trying slowly increasing distances didn't work, and he was at risk of hurting himself. The vet said Bob wasn't safe in a family with children, and the breeder has said she'll take them back (and guaranteed Bob will not be bred). I was asked for advice, and couldn't help. I've never seen a dog this dependent on another dog. Are there any puppy trainers who could give advice on how to manage this? Is it common, or are there ways to train it out of them?