My waterers get slimy feeling in a day. Even with ACV or a little bleach in them. I assume the sliminess is algae or other stuff I would not want to drink. And that's assuming one has figured out how to avoid the litter and poo getting in the water. Maybe auto waterers would get around this; I don't know. I am out there more than daily, anyway, watching chicken TV, so fresh water daily is no problem.
I don't have a problem with viewing them as livestock and minimizing the care. But I suspect that more return is gained with a daily check; so many things can go wrong. They are not bright, can get caught in things or start attacking each other, develop simple medical problems, etc., etc. A few minutes of management goes a long way. Causes me to recall a hen who got her leg caught in a leaf rake. Who would have thunk? She had no idea how to get out.
If I were going out of town for several days, I would feel more or less comfortable leaving them in an environment I had already observed daily. But I'll bet it would cost me someone, anyway....