Anxious Westie Since New Dog Arrived

A Westie who was fine until the second dog arrived — that's a really common tipping point, and the resource guarding on top of the trembling tells me your older dog is feeling genuinely threatened in what used to be his space. How long ago did the new dog join, and is the guarding mostly around food and toys, or is it happening with you and other people too?

Three months in and it's not settling — that's telling you it's not just adjustment nerves, it's become a sustained stress response. The evening trembling when they're both present is classic low-level chronic anxiety, not just a reaction to a specific moment. Is the new dog bigger than him, or roughly the same size?

That explains a lot. A bouncy Labrador pup can be genuinely overwhelming for a small terrier who's used to being the only dog — the size difference makes it worse because he can't read her energy as non-threatening. He's not being difficult; he's coping with something that feels chaotic. What I'd point you toward first is the Adaptil Calm Home Diffuser. It releases a synthetic version of the calming pheromone a mother dog produces, and it works passively in the background — you just plug it in where your Westie spends most of his time. It won't sedate him or change his personality, but it takes the edge off that baseline anxiety so he's not operating at a constant 8 out of 10. That makes him more able to habituate to the puppy rather than just enduring her.

Mostly the general anxiety — and that's actually the right place to start. Resource guarding at this level is driven by insecurity, so if you lower the underlying stress, the guarding often reduces naturally. It won't replace the need to manage their feeding separately and give him his own space with his toys, but it makes those management steps more effective because he's not already on high alert. Most people see a meaningful shift within two to three weeks of consistent use. One diffuser covers a room, so place it in the room where the trembling happens most — sounds like the living room in the evenings.

Yes, a few practical things that make a real difference: feed them in completely separate rooms with the door closed, give your Westie at least one space the puppy cannot access — a bed or a room that's genuinely his — and make sure he gets some one-on-one time with you each day away from the puppy. Westies are sensitive to social hierarchy and he needs to feel secure with you specifically. The diffuser handles the neurological side; those management steps handle the environmental side. Together they give him a realistic chance to adjust.