I am very happy I found this thread but
surprised to learn my thoughts and intuition was correct. Sad to say my puppy tried to kill his sibling tonight.
I have 3 Pomeranian puppies that are just 6 weeks old. Two boys and one tiny girl. The largest one is calm and doesn't have anything to prove. The other boy is very demanding while his sister whines a lot for attention and just happens to be sweet and very cute. They have a large sectioned playground with tile flooring in our den. I play with them, groom them, and spend time with each one individually everyday. I even have my bed set up in the corner to watch them at night. When I sit on my cuddle time chair they run over to me and fight over who I should pick up first. They try by barking the loudest or crying non stop to hurry me up for their turn. I put on my noise canceling headphones and give my full attention to the pup. Staring into their eyes and telling them how much I love them and petting them, scratching, or massaging them. When the timer goes off I put them down and it the next ones turn. I try never to show favoritism and it's always first come first serve. Today my neighbor who comes over 2 x a week to help socialize them with me picked up the two that are fighting for my attention at the same time. He held them for the whole time together. Just before dinner they were wrestling and I kept hearing the girl scream. I yelled "hey, what's going on" I walked over to see the boy bite her leg and swing her in the air and do the death shake on her. I screamed even louder as I made my way over. She got away and he chased her and pinned her down and bite her neck and did the death shake again. I truly believe that her being smaller is like instinctive prey, I think sibling jealousy got him because he had to share his attention time with her. And lastly me yelling and screaming was like a fight instinct triggered. I am going to separate them unless I'm on the ground with them. Also gonna recommend the boy be the only dog in the home.
Also wanted to share when dogs are fighting we would turn the water house on full blast and spray them in the face to let go. Never use your hands to break them up. Their super strength kicks in when they are fighting. I also use this with dogs humping peoples legs. The only problem is the persons leg gets hosed too. Have you ever tried removing a dogs paw grip off a persons calf. Not as easy as you think.
It kinda bothered me when people responded with excuses like they are too young, or they just got carried away, they didn't know their own strength. I can tell they knew it was more just like I did but just didn't want to believe it like I felt. Always trust your instincts with your animals. Never forget they are animals after all. It's their nature to be unpredictable.
I included a pic of my killer.