I have 4 Jumbo Pekins that are meat ducks. I THINK I need to contain and keep them contained so that they can gain some weight and be ready to be processed. Currently, they are roaming my yard with the rest of the flock of layer ducks. But they look so happy with the rest of the ducks. If I don't contain they what will happen when will they be ready to be butchered? Can I keep one or is no possiblity they will be able to mate? I didnt have any emotional feeling toward the meat chickens or the meat rabbits. Why is this happening with the Ducks?