Puppy on a leash

Question
Hi,
I have a 9 week old puppy, mixed German Shepherd and Pit bull, that refuses to walk on the leash.  He sits like a stubborn mule from the old (1950/60s) movies, wanting to be picked up.  He also has the bad habit of wedging a tree/pole between himself and his walker to avoid the leash.

We've had him walk around with his leash for the past 5 days.  He has improved dramatically from his first day.  However, he is inconsistent and unpredictable.  For example, he suddenly sits when walking/running causing scratches to the soil of his leg.

My personal opinion is that he is afraid of something.  However, I cannot figure out what.  I keep looking around to see some trend that would give me a clue and I cannot find one.  

Any thoughts on how to help my baby?
thanks a ton,
Shahram.

Answer
He's just a baby, and this is very common in puppies.  When he stops, let him have a look around, then lure him to come along with you by using a treat (maybe a tiny, tiny piece of chicken or cheese), as you say "let's go."  Gradually, he will lose his fear and be fine.  During the 9-10 week stage, be careful not to frighten him or have him be subjected to scary things - this is a fear imprint period where that can have a lasting effect.  Also, any dog with GSD in it should be extensively socialized as a very young puppy, so sign up for a positive training class right away.  Read the position statements at the American Veterinary Society of Animal Behavior web page.  That will give you some idea of why I suggest early social activity and positive reinforcement training.