A friend of mine found 3 mallard hatchlings by their dead mother and is now raising them, giving them fodder, a heat source, and letting them roam around in an outdoor cage and take the occasional bath. After a very short while they started seeing my friend as their "mother" and follow her around. My friend's plan is to let them out by a lake when they are adult. My question: Will they be able to survive when left in the wild? Or, to phrase it differently: Are mallards instinct-driven enough to be able to survive without having been taught by a mallard mother? Or is my friend better off giving them to someone with domesticated ducks?