I’ve written a PowerShell script with a GUI front end to help in migrating DHCP from one server to another.
You can chose to migrate a single scope, all the scopes, reservations only, or server options only.
Simply select the migration option you want, enter the source server and destination server name, and if applicable the scopeID. Then click OK.
You will need to have the DHCP PowerShell module on your computer (this is installed with RSAT on Windows 8 and Server2012)
You also need to have permissions to make changes to DHCP.
It’s published on the TechNet Gallery – download it from here