All good suggestions here. We had a bad experience with a bird sitter we hired to take care of our indoor birds two summers ago (this was before we had chickens). I had prepared a detailed aviary log and went through all of the routine personally with the sitter before we left on a two week vacation. This was the first time we'd used that sitter, though, and when we got back, we realized she was just not a responsible person. One pair of birds had a filthy cage that looked like it hadn't been cleaned in days and their seed dish was empty; the forage hadn't been put up in another pair's cage, and the last cage of birds had no water. We were very lucky that all of our birds were still alive when we got back!
Moral of the story for me was try out a new bird sitter for a short get away before you trust them for a longer period.