Unless the ducklings are being picked on why separate them from the group. They learn so much more from the flock than we can ever teach them as humans. The moms take turns babysitting and the ducklings learn how to be ducks. Loving on baby drakes can create aggression so I let the drake or ducks put them in their naughty place. My drakes only downfall was that he was so big they would get underfoot and get squished. As soon as moms heard the peeping, they came straight away or the drake would lift his foot off so they could get out from underneath him. I don't keep mean drakes so if he can't get along with the group, he's out. At about 3 weeks the ducklings become more independent and easier to pull from the flock.