Hi everyone, My dog Drifter who we rescued 5 years ago has become very aggressive towards my dog Ragnar who we rescued 10 months ago. They have gotten along great up until recently. Ragnar is 2 and still likes to play and can be a bit persistent. When he gets to be to much Drifter growls at him to let him know to back off. A few times he snipped at him but nothing to bad. We started redirecting Ragnar when we could tell Drifter had started having enough. This past weekend we took both dogs to my brothers new house for the weekend. He has two dogs as well. One is a 6 month old male and the other is a 2 year old female. He automatically started following the female (Lola) around and tried humping her. He stayed by her as much as he was allowed. Ragnar Just wanted to play and had o interest in mounting Lola but Drifter got real defensive, which we understood. After keeping our dogs separated and finally getting home we thought the issue would be over, Oh my were we wrong, it's escalated to the point they can't even see each other and Drifter will even growl through the bedroom door if he smells Ragnar. I'm disabled and can't work with them and there's no way I can separate them, The few times they caught glimpses of each other was intense and thankfully my fiance was able to get them apart. Although now he has a sprained hand due to the last incident. I don't know what to do! I called a behavior trainer who said it was sibling rivalry but they cost $500!! I need advise on what can be done and also I created a gofundme account to try to raise the money for the trainer. Does anyone know where I could post that in hopes other animal lovers will help me? All suggestions are welcomed.. Thanks!