I'm actually observing my ducks doing the same thing now in the morning when they have clean water...only I have all hens...its weird. I think they are just acting upon instinct and that it may not necessarily imply eggs immediately... Ducks as a rule shouldn't be laying that young, it generally hurts their egg production later if they do. My 3 older ducks are all 16weeks right now, I am switching them to layer pellets this next week because I was told a 3 week lead time for high calcium would be appropriate for laying which generally begins at 18-24 weeks. Keep us posted if she does start to lay, I'm so very obsessed with anticipating their eggs, I'll probably call everybody in my family when it happens.