I am thinking that next spring I would maybe like a Sebastopol goose or two. Would they be able to live with my three Mallards, or would the size difference be too extreme? The Mallards would have the "home turf advantage" at first, obviously. Would it be better to get a pair, a singleton male, or a singleton female? I am unsure what sexes my Mallards are (they are still young). I have a large enclosure and pond planned.