Hi, do you mean sickle hocks? Its a little hard to tell with his feathers, and because he's not stood square.
But I do know, correct hind leg structure when viewed from the side is a line that extends from the point of the buttocks down to the point of the hock and runs parallel to the cannon bone, ending slightly behind the heel.
Sickle-hocked horses have too much angle or set to their hocks. The horse's leg stands under the hip from the hock down due to the excessive angle of the hock. I've heard that horses with this condition tend to be outstanding athletes for brief periods before they become unsound.
I've been trying to find you some pics, I'll keep looking.