Alex Cooper has her claws out and is coming out to play ... exposing DMs with Brianna Chickenfry, who's been openly defending Alix Earle -- amid the ongoing Alex-Alix online feud.

The "Call Her Daddy" host took to Instagram, coming in hot, starting her rant with "This girl on girl s*** needs to stop" ... adding, "While Alix tries to get her story together, let me address Brianna Chickenfry" -- a current Barstool employee who has inserted herself into the battle of the blondes.

Cooper claims Brianna is adding onto the "fake narrative and dog pile" by coming online and calling her a mean girl ... but Cooper has the receipts and DMs that, according to her, prove otherwise.

Read those receipts ... the thread begins with Bri reaching out to AC first back in 2022 -- getting ahead of a podcast episode that was about to drop where Bri was edited to trash Cooper and "Call Her Daddy" ... after Barstool boss Dave Portnoy tried to start a hate train between the two women in the episode.

The messages show kind-hearted exchanges throughout the past few years, but Cooper ended the dump clarifying Brianna was never invited on "CHD" ... and pointed the mean girl finger right back at Chickenfry -- adding the Alix Earle of it all is not a PR stunt.

Check the clip ... Brianna wasted no time responding to these messages Cooper aired out online -- racing to TikTok to double down on her distaste for AC and claim -- based on what Alix Earle told Bri during the Super Bowl -- "Alex Cooper is a very, very mean person."

As we previously reported ... influencer Alix Earle and Unwell Network founder Alex Cooper have been feuding for quite some time, ever since AE joined Unwell and the relationship fizzled out due to personal and business reasons.