All I can say and I've said it before, ducks love to fly. One day you might take them outside and one will take off and you may not get it back, I live in the NC mountains with woods all around me and a wild river down below, I have clipped wings for going on 9 yrs because I don't want to lose any of my ducks because they just took off one day for the love of flying and couldn't find their way back or landed on the river and were having too much fun to come home, I have not lost one of my ducks to predation thanks to the good Lord. But if one of them were to fly off no telling what might happen. My ducks are treated really good have lots of food get to free range daily and play in their pools, but ducks love to fly. As far as migrating, I don't know if domesticated mallards would fly off if they saw a flock of wild mallards flying over head or not I wouldn't want to take the chance. Maybe I'm just too protective.