Not long....like don't leave them without it.Does anybody know how long they can go without food and water at this age (approx. 4-5 days)?
It's only the very first couple days after hatch that they can go without as the continue to feed on the yolk in their bellies.

Yeah, maybe. They're purebred Speckled Sussex... I don't know much about the breed, but it's possible that they feather quicker, maybe?