aussie shedding vs. hair loss

Question
We have an Australian Shepherd that is approximately 15 months old. I am trying to determine if his shedding is normal or if he needs to be seen by our Vet. During the past two months he has shed more than usual.  While I realize that this may be his normal shedding process, I am concerned about the amount of hair that he has lost. When we brushed him, he would lose brushes full of hair. His once beautiful full fluffy coat is gone. He is no longer shedding and he does not have an bald patches, rashes or dry patches.  We do have him professional groomed approximately every 6 weeks.  We have always fed him Canidae puppy food, which he has never had a problem with. Thanks for any advice you can give.

Answer
Any time an Aussie displays excessive hair loss, I suggest asking the vet to do a complete thyroid panel to test for hypothyroidism.  The good news is that if the dog has it, the treatment is not expensive.  And, if treated, your dog can live a normal life span.