Look I could be snarky as my disdain for decoys is extremely well known.
I'll choose to not be my normal self. I will however question trying to have a 4 year old kill a bird or heck even a 6 year old. Seems fishy, like dad wants a jump on the season so let's drag the new born out so I can hunt. We've seen it on here before.
Next, why is there this mentality that for kids to get into something these days it's got to be super duper easy? Most of us grew up earning things not having them gifted to us. Such a weird instant gratification culture now. I'm glad I was taught to hunt not kill. I'm also glad I learned range estimating tactics without a crutch.
As far as decoys, it's like kissing other dudes. Just don't start and don't cross that line or forever more you know what you'll be labeled