Completely lost!

I keep getting a range of issues with this project. I am trying to modify a chicken. I either get massive errors, I'd post an example but there have been multiple different ones, or I get no error, and the mesh is either invisible (usually an invisible outline of the OG mesh) or the OG mesh doesn't change at all. I've tried multiple cut numbers, though I think the OG cut number is just 0? Nothing has worked. Some cut numbers give me errors, some give me nothing but with no success. I am at my wits end lol. I am trying to modify the rig too, but I have multiple different version files, some with OG rig, new rig, reference mesh included, not included, etc. I've changed the UV to uv_0, rearranged UVs, Texture + Weight painted. I am sooooo lost on what I'm missing, I've been searching for answers on here for the last 24 hours to no avail lol.

I have no changes to the package file, I don't think at least. But here's the latest copy of my blend file.

WITHOUT OG/REF Mesh: www.mediafire.com/file/w5u1l4ba8qpw522/redhen.blend/file
WITH OG/REF Mesh: www.mediafire.com/file/lll2ekfeduuz3jv/redhen.blend/file

In this version I have cuts set to 0000. I've tried 0, 1, 0001, 001, etc.

Any help is appreciated!