Buy you some .22 lr subsonics. CCI makes some. They are significantly quieter than regular .22. Then move up to bigger guns if they do well. Maybe shoot a few while they are in a bay pen or in an actual bay so they will be distracteded and link the shooting with something they enjoy. I started my female squirrel dog on subsonics because she crawls under my feet if I shoot regulars. Subsonics don't seem to bother her anymore and she is getting used to the regular ones now. She is timid dog.
Great advice.....I agree 100%. I have always carried a firearm of some sort.....I've said this before.....if you hunt with dogs long enough you will run into the situation where you need a gun......sooner or later. Our dogs are quite used to gunfire and to them it means someone has seen a hog. If you start shooting around them as pups you shouldn't have any trouble with them being shy of it later on. Just don't use fireworks.....bad deal there, not good for dogs at all. If they're gunshy now, use the 22 subsonics or CBs as they're called sometimes. Just be calm and give 'em time to adjust, then move up to 22 shorts, then on to centerfire stuff. You'll have to have patience and not get aggravated if it takes awhile to get them used to it. If they're really gunshy try shooting a ways off from them at feeding time, you can't start to softly,.....but you sure can start to loudly. Good luck.
