What breed is this?

Looks lab-ish in the 4-6 months range. Could have some chow based on the tail.

Looks like a small breed cross possibly Chihuahua but without knowing weight and age it is hard to know. It is not a young puppy but probably under six months. You could ask the Vet as they can tell a lot by their teeth.

Thanks both. Will be seeing vet later this month. We basically rescued him when he showed up shivering in the snow.

I'm seeing mostly Chihuahua/Jack Russell Terrier.

Looks older in that picture, I would agree with SueM on the possible mix. Also, could be Chihuahua and Min Pin.