Got home. All the chickens are safe. However, I found out the friend who fed them on Monday put the chicken feed in the cat's bowl. (I know this because it's still in the cat's bowl - the cat wouldn't eat it!) He put the chickens' water in the chickens' feed container. I have no idea if he gave the chickens any food or not. However, since they had water in the feed container, they survived and seem to be doing just fine.
We will get someone else to take care of them next time we go out of town. Although I wrote down detailed directions for my husband for Saturday and Sunday, I counted on him to give good directions to the friend who handled Monday. Lesson learned - and thank goodness all my chickens are okay.