I've noticed that one of my geese has had diarrhea for a little while, but couldn't figure out which one it was and none of them acted sick. Then, a couple weeks ago a few were standing around me waiting for dinner and I heard a weird gurgling sound. It sounded almost like a person's stomach gurgling. It starts quiet, builds in volume, then tapers off. It didn't seem to coincide with breathing and I didn't hear any wheezing or rasping noises with each breath. These gurgles would happen at a regular rate (which is what originally made me think it was breathing, but they were too far apart to be breaths anyway). I listened for awhile, couldn't figure out what it was, and eventually it stopped. Fast forward to a couple days ago. Tuesday night (today is Thursday), I noticed one of my ducks seemed to be feeling a little off (was a little unsteady on her feet). I put their food bowl down and she came to eat as normal. I made note to pay attention to how she was doing. Last night when I went out to feed, she was laying in the corner of her pen with her head down and eyes closed. I brought her in the house, gave her a warm bath, wrapped her in a dry towel, and left her in a warm bathroom. She wouldn't eat or drink and I noticed the exact same noise coming from her! She died a little after midnight. What could this be?