My Aussie wont walk on a leash

Question
I have a 2.5yr old blue merle female. She has decided to stop walking with me in the mornings -- she used to take 1.5 -2 mi walks everyday and suddenly she has refused to leave the yard. She has also started to act fearful when friends come to our home for a visit, wanting me to hold her the entire time they are there and clearly avoiding them.  Nothing traumatic has occurred that I am aware of - she is with us constantly and seems fine when its just my husband and me in the house. Any ideas on how to correct some of these social behaviors?  Thanks

Answer
A 2.5 year old dog should be well past any developmental fear imprint periods, so my guess is that something has happened, either physically or mentally, to create this situation.  It is unusual for an Aussie to love everyone, as most of them do prefer their own family to others and exhibit that tendency a bit earlier in life.  However, since this is sudden behavior that you have not noticed before, the first step is always to have the dog evaluated by a veterinarian.  Things to pay particular attention to, especially with Aussies, are changes in vision, hip dysplasia, and hearing.  If the dog is cleared by the vet, then the problem may be fear related.  Just because you don't know what caused the fear doesn't mean you can't help your dog to overcome it.  That is usually done by classical conditioning  or counter-conditioning with the assistance of a behaviorist or trainer who is familiar with how to do it.  The first thing, however, is to do the vet exam, even if you don't think anything's wrong - dogs can be very stoic about pain and not yelp, etc.  But, a painful hip might make walks unappealing, and the dog might fear being touched by people she doesn't trust, for example.  Hope that helps - let me know how you make out with check-up.  If I can be of assistance with any subsequent behavior modification issues, let me know.
Anne