How to check for mites?
Check around their vent area, usually that is where you can see them easiest.
Any move/change can make egg production slow down, 2weeks may not be enough time for them to adjust, you never know about chickens.
Do they dust bathe?
Here's more information on mite/lice, how to identify and treat:
If you have added new members, as well as, a "new environment" then that is most likely the cause. Give them some time to adjust to everything, hopefully they will settle down soon and begin to start laying.