Is it too late to stop biting/fear aggression?
I have a 6yo female GSD who is generally good natured (with big caveats below). However, every couple of years, I manage to do something or other that triggers a bite - not a nip. Most recently, I accidentally hurt her while trying to put on a new harness that turned out to be too small - result = a nasty bite to my hand, which in fairness was right in front of her teeth at the time that the incident occurred. A couple of weeks later, I went down to give her a stroke on top of her head, as she lay down in her basket. Something that I had done several times in the past with no trouble. This time, another bite - not as bad as the earlier one, but still painful (and on the same hand, which didn't make things any easier). I suspect that the first incident may have made her more wary of me, which meant that the second case was something that was waiting to happen.
She is generally very well behaved, apart from pulling on her lead and jumping at visitors (all in a friendly way). The one thing the really doesn't like is her paws being touched - *unless* she explicitly presents them during a sit, which is nice when it happens. And yes, I know I sound like an indulgent parent of a spoiled child. She is good with strangers and is always respectful of children.
So, can I train her to acquire a soft bite and to allow more generalised touching? Have I left it too late? I really want to get her back on the right path, and I've even become nervous myself of getting bitten again (it is NOT a pleasant experience). Any advice will be real appreciated.
My personal thoughts are: more formal training; counter conditioning of the things that she currently doesn't like; and more exercise, which is a general 'Good Thing'. I'm not a big fan of dominance theories including alpha rolls etc, so I would not be happy applying that approach.