This is such a great question, we just recently had to confine our chickens as well because our new neighbors do not like them. I have a large tire in there(need to get sand) and a perch but looking for other items or obstacles to put in as well.
I saw someone else was growing grass boxes for...
We just found one of our 3 month old chickens in horses water trough we have dried her off and she had a lot I water run out of her mouth but has pooped anything else we should do!