Since we live in the country and already have several kinds of pets, I had a wild idea this summer to hatch some ducks. Sort of an experiment with the kids. My husband humored my whims and built an amazing duck pen out of our old deck lumber. We have one white female runner, and one jumbo pekin drake that were hatched together in early July. They get along perfectly. Since we only had 2, we just hatched out 4 more "heritage" breeds last week. I have no idea what they are at this point, but I am wondering when I can put them in the pen with the older ducks. I know they need artificial heat for several more weeks, but I was more worried about the safety issue. The ducklings have been living in my classroom (6th graders) all week, getting plenty of human attention. Today when I brought them home for the weekend, I let them run around outside with the 2 adult ducks. The drake pekin is a BIG boy. Bigger than pekins I've seen at the state fair. After feigning disinterest for a while, he suddenly mowed them over like bowling pins, but I quickly scooped them up. Will he ever accept them? Do I have to wait until they are completely full grown before putting them in there? They will never be as big as him. My best guess is that they may be Swedish ducks and one Cayuga. Can I put a barrier between them in the pen (it's about 15' long by 8' wide) and let them get used to each other? I was surprised at how territorial he was. Thanks for any advice!