A Book of Sleep by Il Sung Na
The Sleep Sheep by Anna McQuinn
The first book examines the different ways animals sleep.The second examines the difficulties of getting to sleep.
Experiment with listening to lullabies. Make a chart to show who feels sleepy and who does not after listening to a lullaby.
Or you could do the same with “counting sheep.” Provide children with paper sheep and have them gently jump their sheep over a paper fence. Chart who begins to feel sleepy and who does not.