I have four ducklings, about four weeks old. Got home today and two of the four were VERY weak and barely moving, I got them out and took them and sat in a very warm quiet place and they slept for about an hour and seemed to start to get some life back. One of the two was so bad to start with he was almost stiff, his legs were straight behind him, he couldn’t stand or sit or even move let alone lift his head. I’m so confused because the other two are absolutely fine, running around how they always do. Nothing has changed with anything I’ve done with them, just came out and they were going stiff. And idea what might be going on??