Would I be crazy to attempt training my six year old Australian Shepherd to retrieve? Her obsession is playing fetch. We like to joke that she's needs to go to rehab for her obsession with tennis balls. I realize that retrieving a bird versus a tennis ball are entirely different situations, but is it possible to train a dog that old?
I trained my wife's German Shepherd to retrieve birds, retrieve from a dog blind, retrieve from a dog stand, honor, deliver to hand (without force fetch), etc. All just for fun. It can be done however it takes the right dog.