Answered How to run a script before the tag for all pages?

Hi, so I have a website that has more than 1000 pages with a multitude of different templates. What would be the most efficient way to add a script to all of the pages? Basically a tracking code before the end body tag.

I was thinking to add the tracking script into a chunk and then go through every template 1 by 1. But This might not be the most optimal way. Anyone have any suggestions?

Thanks!