Quote Originally Posted by deuterio12 View Post
No, I just happen to actually read the sources.

There's at least hundreds of chaos warbands out there, and each chaos warband is roughly the equal of a loyalist chapter. Since each chapter is around 1000 strong, then simple math confirms that yes, there's hundreds of thousands of chaos marines out there.
Where do you get the idea that every single warband is the equal of an entire loyalist chapter? This is patently not the case; among the World Eaters especially individual warbands are often no more than a dozen strong.