I already have a few chickens and somewhat impulsively bought two khaki campell ducklings this weekend. Lady at the feed store sold me broiler grower to feed them. They seem to be doing ok for the two days I've had them. they are picking out the smaller pieces in the feed, which i think i remember being normal for baby chicks. Any reason I should be concerned about feeding them this rather than some kind of starter? They are a week old at most. Thanks!