I like the cone because the flailing around is contained, but when I did big CX's, their broad shoulders would not allow them to go down the cone far enough that I could get to the head to cut. The biggest one I had to use a rope with two slip knots, but once I cut, I quickly moved him into the cone to finish bleeding. I do my butchering in my garage, so I am very motivated to avoid blood splattering around that I will have to mop up later. I only have Red Rangers left for this year, and their necks are long enough to use the cone I have. If I do CX next year, I may try using either a bucket with a hole in the bottom or a sack.
