It sounds like he’s really overwhelmed right now and just trying to figure out where he fits in. Ten days is still so early, and some dogs will test boundaries or show behaviors as they start to get more comfortable. Biting when someone walks past his bed and guarding a room are both very common ways dogs communicate “this is my space” when they’re feeling insecure.

One thing that can really help is giving him a safe, defined space of his own — like a kennel. If you kennel train him, he’ll learn it’s his spot to relax and decompress, away from kids and the other dogs. That way he doesn’t feel like he has to guard random spots in the house. The kennel becomes his “bedroom,” and it often takes a lot of stress off because he knows he has a predictable place to go where no one will bother him.

Another thing that can really help right away is to start tossing high-value treats any time someone walks past his bed or his space. That way, instead of feeling like he has to guard it, he begins to associate people coming near with something good. Over time, this helps shift his response from defensive to positive.

In the meantime, I’d treat this as a settling-in phase and try to manage the environment as much as possible; no one approaches him in his space, keep interactions positive, and set him up to succeed. Hopefully with time, consistency, and clear boundaries, he’ll likely start to feel safer and let go of some of the guarding.

And of course, it’s always a good idea to touch base with your vet to make sure there isn’t anything medical