I have a good pair a poultry shears but there are getting a bit dull. it's definitely a bit of a struggle and I do not look forward to it. if I had any issues I would not be opposed to cutting out the backbone with my oscillating multi-tool or my small sawzall. I'm just looking for an excuse to use power tools sometimes
I used my wood cutting bandsaw once to cut some beef marrow bones for making stock. Made a horrible mess and I regretted it.
I've also used a Japanese dovetail saw to cut the bone end off a big spiral ham so it'd fit in my oven. That was much easier to clean.