I am having issues with my geese terrorizing the smaller ducks and hens.  The two worst culprits have been removed, but now one of the more mellow geese has taken over the role of bully.  I got geese to help protect the ducks from predators, but who'll protect the ducks from the geese?  
I'm glad your duck is recovering.  Your story worries me because I fear that is where I am headed with my ducks and geese.  I have been hoping that the problems will work themselves out, but I see from the pictures of poor Nibbles that I may have to be more proactive.
Thanks for sharing.