I stopped using playpens and start using Kidco Sleep pods. They can't stand up in them. I find that they sleep much better and longer in them. It can take up to two weeks for the child to get use to them, but once they do, nap time is much better.

you can try rubbing the childs back and singing softly. I don't recommend rocking the child. When we have more then one child in care, its not practical. The child will learn to sleep at daycare without being rocked, it just might take a few months.