I have 2 ducklings who are 6 weeks old, and I am more than ready to have them out with the rest of the flock. We live in Michigan, it I very cold this winter. The ducklings have most of their feathers at this point. What would be a good system for introducing them to the flock? I have a small fenced in coop inside the ducks daytime pen where I could put the babies. They will be able to see each other without being able to pick on them. At what point will there little guys be safe to spend their days and or nights without the heat of out house? I'm anxious to be done with the poop!