I have three shepherds and they are all a year apart. My oldest male is 4, his daughter is 3, and the baby is 2 and he is a white GSD. The youngest is the largest, and the other two jump him. I figured that he would eventually fight back, but has never gotten to that point. He is a big baby who is just a sweet and gentle animal. I need advice on how to keep him from getting hurt by the other two. My brother has his brother, and I am being told now that the his temperament is the same way (another dog can jump on him and he just lays down and takes it) but he is not around any dogs that are able to physically harm him. Is there anything short of keeping the other two away from him that can be done to change this behavior? None of the dogs are aggressive to other animals, except for the two jumping on the one. Any suggestions would be very much appreciated, as I do not want to have to re-home any of my animals and I would like for them to live in peace together with me.