I have regularly left my hens on their own when I have to leave for work and be gone 2-3 days at a time each week and have been doing that for the last 10+ years.
My family is home but they have no interest in my chickens other than eating their eggs. Even then they won't collect eggs unless there are none in the refigerator for breakfast. My daughter will go in a play with them while I'm gone so I have child proofed the door so it always closes and lock behind her.
I don't have the extreme tempatures that you guy have on the mainland, my temps are always between 65-95 day in day out. I do have 2 automatic hanging water bowls and a 25# hanging feeder that I always make sure are clean and topped off before I go to work. I have had a water bowl get plugged, but never both at the same time. I have never had a problem, my coop is pretty much self running. I have never come home to find my chickens in trouble.
Even when we go on long vacations, I have my friends come over every 3-4 days just to collect the eggs, top off the feeder & clean out the water bowls. I have never had a rotten egg before. Remember that hatching eggs have to sit for 10 days and still be good, i.e not spoiled, to hatch. I have found that my coop can go over a week without running out of food. The only problem I have had is too many eggs in the 1 nestbox and a couple getting crushed, never mind they have 4 boxes to choose from.
If planned and designed properly you can easily leave your girls alone for a couple days. Now there may be some seperations anxiety at first, but I'm sure YOU will get over it and have a great vacation.
Aloha,
Cory