I started hiking with her at 15 months in preparation for a backpacking trip at 18 months (no pack on her at that age). The distance running started after the backpacking trip.
As for training - easiest dog I've ever had. Smart and eager to please. I haven't seen any of the "stubborn" that you read about. Take the time to learn her language (she's trying to learn yours) and you will have no problems.
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