Our two pups are crate trained, we found it really easy as they had two nice beds to start with in a pen area together. When the crates came we just put the beds in the crates left the doors open for a few days (in the pen still) and they automatically went in to their beds. We then moved onto shutting the door at night and never had a problem all the way through.
Are your dogs crate trained? How easy did you find it and how beneficial do you feel it is?