Always will be a farm dog, we had a bluey called Boss.. no matter how much you try the ankle nipping was always there, without a doubt it is instinct and over time did become less and less but on rare occasions a small nip just to show who is still the boss. Nothing drawing blood more of a gummy nip.
The worst habit was when your standing looking into the distance and he’ll be right in front of you then with that snout nose you in the balls! Only ever did it to males and never females... maybe he knew?
