Many professional trainers believe that hard mouth can be a hereditary affliction. When selecting a puppy, by all means check out the parents first. Still, there is really no surefire way to tell if a dog is going to be predisposed to damaging birds once it grows up. That part likely falls in the luck-of-the-draw department. There are, however, precautions you can take while training your retriever puppy that may help prevent the dog from developing hard mouth. Common sense applies in most cases.
If you donāt know the dog, youāre probably right that itās not worth the risk. Iād guess those 2 have been friends their whole life though. I know with the golden I had that she was always great with any person or animal she came in contact with.
Itās always a risk. Would you want your best friend to go into a polar bear enclosure alone even if the bear had never mauled anyone or acted like it wanted to?
Itās never worth the risk if you value the little birdās life.