Chris, back when I was fooling with a lot of Labs, I always fire red 22 Blanks off when I fed them. Never had a gun-shy Lab but have had several Plotts that were mostly due to bad shooting on the hunters part & not waiting until we got the young dogs back. Had one idiot with a AR-l5 & shot about 5 times scaring the hell out of some young dogs.
Now my Grandsons are always popping their bull whips & the young dogs have gotten so used to them, it never bothers them anymore.
Bingo, thats exactly what I was about to say. I start out banging pots or pans together loudly right before I feed em, they associate the noise with food pretty quick. Then after a couple weeks I start using .22 blanks. I will feed then walk off and shoot a couple times 60-70yds away, they rarely even flinch, over the period of a couple weeks I will gradually get closer as I shoot, before they know it I am standing next to them shooting it and they pay it zero attention.