I'm going to get shot down for this, but here goes
However miserable they are now, it's only going to get worse as winter wears on, the muck gets colder and the ground gets harder - if they're having trouble walking now
Add to that starvation (okay, so we know it's not starvation, but they don't) and they will be pretty blimming miserable I'd think.
I'm not a hard hearted person, really I'm not, but I think you'd be better to think about slaughter sooner, rather than later. Having bought 2 VERY overweight Kunekunes myself in the past and tried to slim them, I can tell you it's going to take a long while and it's going to need them to move
lots. We dieted our 2 for almost a year, they maybe dropped 10Kg
Give them another few days to a week (the benefit of the doubt) and if you're not seeing much improvement it might be in their best interests to go.
Sorry, wish I had a gem of wisdom for you
Karen x