I have 3 Welsh Harlequin ducklings that hatched a few days ago and I found a lady not far from me who has Cayuga ducklings that also hatched the same time and I'd really like to add a couple to the brooder the Welsh Harlequin ducklings are in. Do I need to keep them separated for any reason if all appear healthy? They should of course be about the same size. If I keep them separated, how long and how should I add them together? I'm mainly worried about each set of ducklings having different types of bacteria and getting the other ones sick. Thanks!