submissive /shy wont respond

Question
We just got an 18 wk old mini Australian Shepherd from a reputable breeder. We can't get him to get up and move at all. He is alert, has been checked by our vet. He is active with our 5 year old red heeler mix when they outside...not really playing - just running / following along. However, we have to carry him ouside. He will not come or even get up when called. He will eat and drink if we carry him to the bowls and we do find an empty bowl in the mornings, so he is eating after we all go to bed.  He is evry affectionate and obviously no trouble to handle - as long as you're willing to step over him to get to the couch.
We've never seen a dog that doesn't move!

Answer
It sounds to me like a case of poor early socialization.  Puppies are remarkably less accepting of new things after 12 weeks.  The period between 6 weeks and 12 weeks is extremely important in a puppy's mental development.  If it spends that time in the breeder's kennel, it may never do as well in a home as a puppy that went home at 7-8 weeks.  Have you let the breeder know about the problem?  I am afraid many so called reputable breeders fail miserably when it comes to socializing puppies.  

The puppy may come around in a few days with lots of attention.  The logical thing to do is return it, but we are not always able to do the logical thing.  I can give you some exercises meant to help bonding.  

''Elevation for small puppies: Sit on the floor and gently put your hands around your pup's middle, below his front legs, and lift him up. He is facing you. Hold him for 15 seconds. Repeat until he no longer struggles. If he is past 10-12 weeks, lift his front feet off the ground, but don't pick him up.

Cradling for small puppies: Hold your puppy gently on his back, as you would cradle a small baby. If he struggles, hold him firmly until he quiets for 10-15 seconds. With larger pups, you can do this as your sit on the floor, with your pup between your legs.

Quiet lying down: Place your pup on the floor on his side, with all 4 legs pointing away from you. Use your hands on his neck/shoulder area and middle, to hold him in this position. When he is quiet, praise him. Lengthen the time that you keep him quietly in this position. When he accepts this position well, handle his paws and muzzle, while keeping him quiet.''

The quotes mean this isn't my original work. It is copied from my Puppy Raising Manual. I have long used these or minor variations of them, and they are very effective. You may want to give him a belly rub while he is on his back too. Helps bonding. There is a big difference between him rolling over and demanding a belly rub, and you choosing a time to roll him over and rub his belly. The latter cements your place as pack leader.