The 3 unset corners must spin in the same direction, they are collectively spun clockwise + or counterclockwise - so no need for special numbering, and only one spin identification is enough to qualify the collective spin. C2 is always set and the other unset.
The chicken's head is C2, legs horizontal and wings vertical, so looking to the left. But we can also imagine legs are vertical and wings horizontal, hence looking to the back face.
|y R U R' y R' F R U' R' F' R y|
|y2 R' U' R y' x' R U' R' F R U R' x y2|