Thanks for asking! After a week of confinement she was still getting slowly worse. I rang the vet and described the problem - they prescribed antibiotics which I'm giving her every day. Today is the third day, but already she's standing more comfortably than she was, and seems less aggressive. I'm really keen to put her back outside, I may have to wait until the course is finished, though, as catching her is difficult and stresses her out. The other three ducks have found her, and because I leave the utility room door open because of the smell, they come in and chill out with her. Unfortunately they also poo everywhere so I'm going to barricade the door!