LOL they can all be a hoot can't they. The stalkers are the Mallards and they are so tiny. lol So you already know the drill good for you!!the age difference isn't ideal I went through a local chicken store (yes this guy has a chicken store and it's awesome) to order the ducklings and he ordered 2 the first time instead of 6 so we had to wait for the others to come in the mallards were a fiancé acting like a kid begging me to get them for her lol. The 2 older runners are in the same brooder as the bigger mallards we have a divider where they can look at each other but not get to each other. we call the mallards the stalkers since they are always leaning as far over to look at the runners lol