I bought 3 swedish blue ducklings last week from the feed store. (2 females, 1 male). I actually went to get runners, but the store was out, and these guys were SO cute! Anyway, the feed store will have runners again tomorrow, and I'll probably go get a few little females. My question is, will they be okay just sticking them in with the older Blue Swedish? I realize there isn't a huge age difference, but the Swedes are getting HUGE already. Any thoughts?