You know, Ive used sugar water, gro-gel, electrolytes, yougurt, in all sorts of combinations, moist food and dry but the best thing is adding ACV with mother. Hands down, no competition. About ten years of experience.
I tried Gro-gel b/c it is a neat idea, but difficult to work with. Chicks dont' like the sensation of having stuff stuck to their beaks, so they don't eat it very well. My guineas liked it way better than the chicks did. I mixed it with very little water and smeared it onto clean areas of the towels in the brooder. Kind of like spreading jelly really thin, that way it was so thin that it had less of a chance to get stuck on their beaks. I tried to make it crumble with little success.