Great question — answering as the UphillTech team:
Google allows Multiple tracking codes on web pages . However, some configs may not be supported. You can install multiple instances of the Google Analytics tracking code on your web pages to send data to multiple properties in your account. Not all configurations are supported. You can, for example, install multiple instances of the Universal Analytics tracking code (analytics.js) on your web pages but only one instance of the Classic Analytics code (ga.js). Multiple instances of ga.js might result in inaccurate data collection, processing, or reporting. You can, however, install one or more instances of analytics.js on web pages that also have a single instance of ga.js. Using multiple...
Full answer by nunorbatista: https://webmasters.stackexchange.com/a/72268 (CC BY-SA 3.0).
Need it done for your business? UphillTech.