If there is no pine shavings to get in the water I suppose they can be left unattended. My immediate thought was no way as the water needs changing once or twice a day in my brooder but that's due to pine shavings getting kicked into it. So with a towel or such flooring and larger water and feed dispenser that wont tip over (another thing that happens in brooders) they'd have enough water and food to last a weekend.
You'd only know if it works by trying it before you leave. Make a set up that you think works and see if it stands up for two days without intervention. If not then you need a person to come in once to provide water and feed.
Ok, thanks! I would have someone feeding my dogs anyway. They could check on them, If the brooder is pretty large in relation to the chicks' size, hopefully the poop wouldn't build up too much. I don't think my dog sitter would be down for cleaning up chick poop.