What is wrong and how do I fix this??

[nuthatched]

They are about 1 and a bit years old, they have just been having a duck mix from the local produce store. There is no brand it’s a big white bag full of seed but it has served them well all this time.

Is there an ingredient or nutrition label?

 

[Reuboid]

Get them to eat activated charcoal. It will absorb toxins. And it won't hurt them if it isn't toxins. From your other posts, it sounds like you're in Australia, which to us northerners is known as the Land That Wants To Kill You In Any Way Possible.

It did want to kill in anyway possible and it did. A snake or a goanna came and took a sick duck with no body to be found. Our last duck still has a chicken and I feel like she must have seen the body because she isn’t calling out for her sister at all. She isn’t sick anymore and the charcoal did work on her so thank you.

 

[Canadian Wind]

I'm so sorry to hear this *BIG HUGS*

I am glad the charcoal worked. But that means your ducks ate something toxic, and you'll have to figure out what it was and remove it.

You may not feel like it right now, but you'll need to get a companion for your duck (and chicken). Being flock animals, they need the company of others of their kind.