On the feet, are you using tape, a slip knot crafted with a half hitch (nylon, I assume?), or????
I use a piece of 1/4" (maybe 3/8"?) woven cotton line with a slip knot that I usually double around and tie another half hitch around the feet for double protection. The cotton holds the slip better than nylon and ties more securely around the feet. I would go through way too much tape on a butchering day if we used tape for every one, but it sounds like a quality electrical tape could be a decent solution if you are only butchering a couple at a time. We butcher 60 or 70 every couple weeks in the summer.