Oh no, I’m so sorry. Both of them dying so suddenly makes me think they were possibly exposed to something. Had anything changed in their environment recently? Did they have a heat source and if so, what was the temperature of the brooder?
Oh no, I’m so sorry 😞. It sounds like you tried everything you could. We lost one of our first ducklings—it’s so tough.
If it’s not too soon to think about this, do you have a way to get another duckling or two? Your remaining duckling will do better raised with other ducklings.
Do you have a feed store nearby? If so, I would pick up some Sav a Chick electrolyte and probiotic packs and add those to his water. I don’t think there’s much that you can do other than continuing to make sure he drinks water every 20 minutes or so and that he’s warm and comfy. Also, separating...