Border Collie puppy

Question
We bought a Border Collie/Australian heeler mix puppy from our local humane society (this is our third dog we have gotten from there).  First, they told us he was 1 year old, our vet tells us he is 6 - 8 months.  He has NO hair on the inside of his thigh/leg, almost like he was shaved, but we've now had him two months and no hair is growing back.  I can't see any scars.  He was microchipped and neutered BEFORE being put in the humane society by the owner.  I know Border Collies are "nervous" dogs but he seems to be extra nervous and afraid.  Perhaps he was abused?  Two main problem with him:  1) separate anxiety from me (when I leave, he whines, runs from door to door, whimpers, etc.)  We've tried the radio thing, he has lots of toys, etc.  If he is outdoors when I leave, he will immediately (within 1/2 minute) start digging his way under the fence or trying to get over the 4' chain link fence. 2) is that he wants to be on top of everything -- counters, dining room table, washer and dryer, top of the back of the couch -- is this a "breed" thing?  Or dominance?

Answer
I don't think this is a breed thing,but rather a dog that is insecure and afraid to be away from people

The best thing to do here,would be to call up several trainers in your area,and ask them if they deal with separation anxiety,and there are a number of trainers that do-but be cautious of trainers that want to put the dog on medication without working on other solutions first,while some dogs that is the only option,it should be as a last resort only

Some dogs do have to go on medications,such as Prozac,but only under the direction of a vet and only after you have tried everything first-and do NOT crate the dog,unlike being destructive crating will make the problem worse