I'm coming from the perspective of treating critically ill human patients, not fowl. If the body is so traumatized it cannot absorb SQ fluids, then it will not absorb fluids through the gut, either. That's why tube feeds in the ICU are only done at a very slow rate to keep the intestines from dying, not to nourish the body. Resuscitation is done through the veins, and if not, the into the bone marrow in an emergency. You never fill up the stomach with saline to try and save someone.
I know in other animals, SQ is recommended for dehydration since the gut shuts down and if you tube in water to the stomach, it will just be thrown up, increasing the risk of aspiration.
But like I said. I know very little about ducks, I'm not a vet, and the way I treat my animals is based on knowledge of people - which I'm sure could be way off base at times. It's a good question and I probably humanize my answer since I would rather have some fluids injected under my skin than have a tube shoved down my throat.
Now c'mon, Spice, heal baby!
