I guess we must have been very lucky. We got litter mates 2 years ago, Tuke and Zoey. Just to let you know, Tuke is a girl. We have had none of the problems mentioned in this thread. They have been absolutely fantastic dogs. They were separated during training and sometimes during exercise, other than that they were together. Zoey is a Velcro dog big time, while Tuke is a great kid dog, when the kids head out back, she's usually right behind them. Zoey prefers to stay close to my wife and I. I'm guessing it's their polar opposite personalities that has made this work out so easily.