There's a couple things we do. As a general rule we frequently talk about our food in terms of wear it comes from:
"What's for dinner?"
"Dead cow."
"What did you fix to eat?"
"Chopped up a dead chicken. Tossed in some noodles. Want some?"
"Anybody want me to burn a dead pig on the grill this weekend?"
Stuff like that. It sounds gross to people who don't know or appreciate where their food comes from, but all my kids have taken it in stride for more than 20 years. The most embarrassing thing was sitting in a restaurant with my oldest who was almost 4 at the time and when the waitress asked, "What would you like, honey?" and she said, "Dead cow." Not the kind of thing you'd expect to hear from a cute little blue-eyed blond in frills and lace.
The other thing you can do is make the children feed, water, and clean up after the turkeys. In all kinds of weather. In fact, don't let weather be an excuse to let them shirk their chores. Tell them, "You want to eat when it rains. So do the turkeys. And they can't get the feed from the bag themselves." Kids love feeding baby poults, chicks, ducklings, goslings. But when I say, "Here, I cleaned out all that old salad from the refrigerator. Take it out to the pen and give it to the turkeys," in the middle of a video game, it's not as much fun. That way, by the time August or September rolls around and you ask, "What do you think? Should we take them to get processed?" they are more than ready to say, "Please. Can we do it today? I don't want to have to clean one more drop of turkey poop off the back porch."
Seriously, though, we have never once had a problem processing any of our turkeys. The very first year my daughter was in 4H for turkeys, she rode with a bunch of her middle school friends who also raised turkeys that year to the processor and watched the whole thing. By this time, they were tired of spending every day at the fair cleaning out cages, showing, pushing, pulling, hauling, cleaning and everything else. They were all tickled pink to have them in bags and ready to deliver.
Another solution is to go with heritage birds that serve as your brood stock. Keep a tom and a hen or two over the winter and let them hatch out poults. Keep the older birds as the pets and the babies for market. To me, that's the best of both worlds.