I used to do the standard 'one finger per string' technique for fingerpicking. Recently, I started doing this alternating picking with only the thumb and forefinger for single line riffs. It is has a similar feel to alternating up and down strokes with a plectrum and I seem to be able to pick single lines faster this way.
Chicken picking, is where you hold a pick between your thumb and finger, and pick in both directions, PLUS, use a couple of fingers for the treble strings as well.
The picking in question from Yukio, kind of has a Chicken picking vibe, yet I believe what sets it apart from chicken picking is that he's not picking in both directions with his thumb.