When we used to go away for a couple of days, I always added an extra pan or two of water for the chickens. Just in case they tipped their water font over. I had a time when I arranged for someone to take care of my animals and they didn't, so I'm always paranoid about that, too. I like to have them set up so that they'll still be alive when I get home, no matter what someone did or didn't do.
I also leave a paper with a few notes on it. People can seem to be listening and think they understand, then after you get home they tell you they couldn't remember something. Now after I get home, they usually all say they appreciated the information I left.