If you want good maternal instincts you'll be looking for a chicken hen not a duck hen!
Ducks are far more relaxed about their young; one of mine gets very aggressive when she has babies - she's not bothered about me handling her young (she left them asleep on my hand for an hour on day 1 while she went foraging..), she's only bothered about me touching anything she thinks is food!
As long as they're not constantly standing on or attacking their babies - then you have a "good" duck mum![]()
Funny!