Step 5: Tie legs
Bring the ends of string down between the chicken's legs, then cross the legs at the "ankles" above/behind the point of the chicken breast. Make sure your previous knot is still pulled tight. (You could turn it into a square knot if you need to, but I just keep tension on it during this next part.)
Separate the strings, loop them around the outside of the chicken ankles, then tie a square knot to finish it off. The legs should now be cinched in close to the body.