It's like regular childcare, except with more dogs, and less care. The idea is simple, but will take some finesse to perform.
1) Construct a box. It should be 3x3, leaving a 1 tile center free. The walls should be wall grates and the corners should be actual wall. Alternatively, perhaps ideally, the center tile could be a floor grate (not a hatch). The roof should be either a floor grate or a hatch.
2) Place a child into the box. Creative abuse of levers, wall deconstructions, and hatches can be used.
3) Place 12 years worth of ☼Dwarven Syrup Roast☼ and assorted booze into the box, by "dumping" it onto the roof and then opening the roof via lever, causing the items to fall down. For this reason, the floor would need to be solid to accommodate a food stockpile.
4) Place a female dog in the box.
5) Wait 12 years to unleash disaster.
The premise is fairly simple. Animals enclosed in a tight space will lash out randomly, often attacking a dwarf in the same tile. This extends over time to create a biological danger room, where the dwarven children are subjected to 12 years of consistent dog biting, scratching, and watching the dogs kill each other, quickly leveling up the child to legendary dodger, perhaps wrestler/kicker/biter/etc if the dwarf manages to counterattack. Not sure if a dwarf will counterattack an animal. The child will eat the food from the floor that he's been staring at for the past 12 years, and will ideally be comforted by some lovely mist falling right beside him. Once the years have passed, and the child grows into a scarred, hardened, tough-as-steel dwarf (don't forget agility, endurance, etc) who doesn't care about anything. Or, keep the lid closed, and throw in a weapon and shield, and replace the dogs with goblins.
The only issue is trying to get the child to survive without going berzerk. But then again, that might just turn into training for the other caged children, right?
Design ideas or implementation, anyone?