I am experimenting a lot with the game right now and one thing I have noticed is that child dwarves are extremely useless. They just throw parties and interrupt others.
It's obvious they need to be sent to a better place.
My current solution is to dig a 2x2x8 well with a bridge on top, use a burrow to get the children onto the bridge and then just pull the lever. Most of them immediately die, some of them need a few months to meet their demise.
The problem is cleaning up the bodies and putting them into coffins. This creates a lot of unhappy thoughts but I do it to avoid ghosts being spawned.
So what is the most clean way to get rid of children while creating the fewest unhappy thoughts in my dwarves?