Hello, I have had experience with several dogs however I just got 3 new puppies! One is a 12 week old Morkie, the other is a 11 weeks old West Highland Terrier, and the third one is a 9 week old Goldendoodle. The 2 small ones- Morkie and Westi get along fine, however when we mix in the Goldendoodle there seems to be some issues. The Morkie and Goldendoodle do well together however sometimes the Morkie will growl and get mad at the Goldendoodle because he is so big and sometimes plays way too roughy for the little guy by biting his ear and tail. As for the Westi and Goldendoodle things get worse- they are good then suddenly one starts growling and they have actually got into a fight and started biting one another, so we had to separate them. Sometimes the Westi will growl at him for no apparent reason but they will lay by each other and let me pet them and be just fine; but when they play or are unsupervised they get very aggressive. My boyfriend and I have tried so many things from treats to slowly getting them together but nothing has worked so far. If anyone has some advice or experience with puppy aggression that would be great. I really want them to just get along, if not we might have to give away the Westi and I really don’t want to do that.