I believe norns generally have a tendancy to get "fat" and for CFFs this is a pretty major problem, I believe there were fixes that were applied to their livers (or equivelent) that while it fixed some problems it made them much more susceptible to the effects of obesity.
True! That's one of the first things I've noticed while developing these. The latest version (3) that I've listed above should not have a tendency to get very fat.
Currently, I'm checking out how the C3 standard breeds and mall breeds fare with these changes. So far the only ones that needed a few extra edits were Treehuggers.