I noticed how he went back and forth with the dubbing in the previous video. That's not supposed to work!
As for his hackling technique, not that dissimilar from that espoused by Art Scheck in Tying Better Flies. Scheck, however, leaves a tiny triangle of the tip in order to keep the feather from pulling out accidentally. Arrick seems to remove the entire tip.

Not cutting the thread after starting the fly is a Charlie Craven trick.

Btw, why is it (in both threads), Arrick's of Arrick's Fly Shop as opposed to Arrick of Arrick's?