My husband was grown up on hunting to eat, where they were in Maine, it was very normal- still is. He went hunting the first time at 6yo. My dad's always been a hunter- says the girl whose birthday falls during the week-long hunting season dad would take... LOL but the MOST he ever had me do was pull feathers from a duck & a pheasant he got when I was around 14 or 15. I became a vet tech later in life & realize I am not a killer as much as a saver, so it's really hard for me to kill an animal unless it's obvious it's best for the animal. BUT I shocked myself when I realized once it's dead, I'm perfectly fine skinning/butchering an animal. So be it, DH is more than capable of doing the deed for me & I'm more than capable of handing all the 'gross' stuff later lol
Our son was always present when DH would bring home a deer, so he's seen his share of dead animals, with the emphasis of 'we're going to EAT this' (ya know, opposed to when a loved family pet has died). He's always been allowed to 'help' if he wanted, occasionally he'll help pull the skin during skinning, but then loses interest & goes about his day. This year DH got a deer & our son (7yo) was involved from skinning, to dismembering, to washing & grinding the meat. I was surprised he stuck with it for so long as he's high-functioning autistic.
I had to cull a layer hen a while back & he still thinks she got sick & died, only because we were all attached to them. But for meat chickens, I'm not worried we'll get attached to them as in 'pets' that we have with the layers & I plan on letting our son help out- not with the culling process though. I think I'll give him a couple more years before I let him witness that one lol. But he's already in a more reasonable place with respect to killing to eat, etc. than most people I know.