My little boy is just over 10 months and has never really slept through the night. He averages 5hrs before waking up for a drink. Lately he starting moving all around his cot and for most of the night. He won't lie in the same position for too long, he lifts his legs and thuds them down on his mattress, throws his arms around and rolls over onto his front. He's asleep all through this and i'm really worried he hurts himself on the bars. I know a cot bumper would help but don't quite understand why this has started happening. My husband and I barely sleep listening to him move around and get out of bed to check on him. Can anyone offer any advice?