Fall 2020, I took two deer in South Texas and left them at the processor. When they were ready, I removed the right stick, right seat, and the smoke tank (mounted behind the copilot seat). I used that space for a medium sized ice box which fit perfectly in that space. I also used two smaller ice boxes which fit side by side in the cargo space.
Luckily, these were smaller animals, so all the meat fit in these containers. A larger buck might have been more of a challenge.
Weight and balance were fine even with the ice. Zero problems flying it all back to 52F from KGTU at 9500'.