Lol I do not want to get complicated like this which is why I want one food to start feeding them when they are mature and to keep feeding them at least until they are too old to lay eggs any longer. I think a 17% protein ration will be good for them year long even if they quit laying in the winter. But I read non laying ducks need only 1% calcium and if they get more calcium, it can cause kidney failure. Laying ducks need 3-4% calcium. So I'm wondering if the ducks do stop laying in the winter, will this feed provide a dangerous amount of calcium? I'm new here so I have no idea.