Thank you. She's been eating chick starter. It doesn't look mouldy and it is stored inside out of the wet. She has a wooded yard to run in so eating something toxic is a possibility. I gave her supplemental powdered niacin in water when she was younger.
It's been anywhere from 90-100 degrees here, but today was on the cooler side and she's definitely acting different from the other ducks.
I'm not sure if she's laying yet because she moved in with the other ducks at 4 months old so I don't know whose eggs are whose. I did get a couple of tiny eggs recently so they could have been from her or my other young duck.
I have 2 drakes, one is a year old and pretty much leaves her alone but still has access to her, and the other is her own age and has mated her.