Gosling can't stand up
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If there's a TSC or other farm supply store near you I'd get some nutri-drench and brewers yeast to put in the water. I can't speak from geese experience but our most recent duckling that hatched took a while to become steady on its feet. Warmth, water, some crumble food soaked with water initially and vitamins and niacin will help the best. Hope this helps.
So sorry for your loss. It's always tough. Especially when there's no clear indication of why. We lost a goose last year after having him / her for less than a month. He or she was doing great with the other gosling we had gotten and we come home from work one day to find him or her laying on the ground. No idea what happened and no visible signs of anything wrong or harm by predators.
I'm sorry you lost your little bird. I'm not on here much. Next time, just try brewer's yeast. The Nutri-drench has a lot of good stuff, but also a lot of molasses, which can cause diarrhea. That's the last thing a stressed little bird needs. I learned that the hard way, too. I make a paste of the brewer's yeast (TwinLab Super Yeast Plus is what I use) as thick as they can tolerate it with an eyedropper. I add it to all my goslings' feed. It's helped them get over the rough spots and contains whey and other vitamins that can keep them going. Sometimes not even that works, despite our best efforts. Again, I am sorry that happened. It's hard to lose them when you work so hard to help them live.