My last dog would have been more stable, mentally, if I *had* let him chase down animals. One of the things his breed was bred for was extermination of vermin around farms. He was super frustrated and unruly when I did *not* allow him the chase because I was denying him what humans had told his ancestors to do for hundreds of years.
I would argue that you did not display proper leadership. The breed is always a factor, but 90 percent of a dogs' behavior has to do with upbringing. Was your dog by chance a Border Collie?
I'd imagine your last dog was not getting enough exercise and confident direction. And honestly, this is hard. It is difficult to read a dog and train him, since each individual dog is so unique, regardless of breed. But to blame it on the breed is petty. The hardest part of it, honestly, is that dogs can easily read your mind and tell how mentally stable you are. If you are stable, they will respond submissively but if there's a crack in your confidence, they will always sense it and that's why dog trainers have so much trouble. The dog trainer has to be a stable human on his own, before he can confer such stability and alpha-role leadership to his dog.
I would like to say dogs are tractable enough to eat food without killing to eat it. And so are corn snakes... which shows that there IS a similarity!
I only fed live to my snake, because 1. I wanted the snake to have the natural experience of "hunting" and 2. I admit I wanted to watch "nature in action" which could be attributed to *gasp* latent sadism.
I admire your ways of respecting both snake and mouse, and finding the most decent way for both to carry on. I just have difficulty respecting both predator and prey, seeing as one is surviving, and the other is a hapless victim. How can you respect both at the same time?
Giving the mouse a "humane" death is sterilized cruelty, or "humane euthanisation" in your terms.
The organization I work for is strictly against dog euthanisation, and I understand why. Killing is killing, no matter how you slice it.