Please help!!! My duck is hurt

I need help my duck hurt her leg and I don't know how to help her !!!she has been an in side duck recently me and my wife bought her a large outside fence area that she seem to have lots of fun we put. A pool and everything for her but we came home one day from work and we noticed she's limping, it's been 3 days now and now it's like she struggles to walk we pick her up and she seems to be fine but we place her down and she struggles her foot is swollen