Hello! I have a now 10 week old black lab puppy. My brother’s 3 year old dog (mutt, unsure of breed) is extremely jealous and has gone after the puppy growling and barking and biting her(not playful) 5 times now. We live together so it’s hard to separate them all the time without the adult getting upset. They will play sometimes however the puppy has her hackles up. Now when she plays with other puppies she seems very aggressive and has her hackles up as well. I’m not sure if she has adopted this aggressive behavior or if it is normal puppy play. I am very concerned and do not want an aggressive pure bred lab.
For a puppy to have her hackles up when playing with other puppies isn't normal play. You need to find a way where your brothers dog can be 'free' to suss out the puppy while the puppy is safe in your arms. This way the puppy won't feel in danger and your brothers dog can see what 'they' are as remember he has been an only dog for a while. It might be easier to try and do this in a park or new place for both dogs, remember that house if the older dogs home and you have brought something new into it. It will take time but for now I would say your puppy needs to be separated from them in the house and start the 'get to know each other' again but outside first. Make sure your brothers dog doesn't feel 'put out' and that they still receive loads of attention. It will be a training for both dogs but once done will be worth it when they can curl up together
