'Duck Dynasty' -- FAMILY DIVIDED ... Battle Lines Drawn Over LSU vs. Alabama

A civil war is brewing inside the "Duck Dynasty" family -- a war that threatens to tear them apart from the inside out ... and it all has to do with one of the biggest rivalries in sports ... LSU vs. Alabama.

The family lives in Louisiana ... so you'd think they'd ALL be diehard Tigers fans, especially since Bama folk are so bitterly despised in the Pelican State.

But when Korie and Sadie were leaving Craig's in West Hollywood this week -- we asked if they were all pulling for the Bayou Boys when they take on Alabama on Nov. 8th ... and were SHOCKED at what we heard.

Listen closely to Sadie's answer ... it'll make any Tiger fans' ears bleed.

And to make matters worse (or better if you're a Bama fan) ... turns out Sadie has been supporting the Crimson Tide for a while -- and even sent some "Roll Tide" love to A.J. McCarron last year.

No word on how or why she became a Bama fan ... but we put some pieces together and it seems like it might be the same reason teenage girls all over the country piss their families off ... a boy ... who happens to live in AL.