Nah. He didn’t. The snake that Daryl stabs and then eats in The Walking Dead Episode 412 sure looked real in its death scene, but no snakes were killed on film.
Comicbook.com asked AMC directly, and their response was a terse but to the point “No.” The American Humane Society monitors the animal action on the show and wouldn’t let that happen, but, you know, internet, so a controversy was forming about the issue anyway.
The snake that Norman Reedus acts with was very much real, however, according to Reedus on an appearance on TheWrap’s Drinking With The Stars. The “snake” Daryl ate was really eel, Reedus said on AMC’s Talking Dead.