Interesting read - thanks for that.
I would certainly be interested in slaughter 'in situ' as it were - it intuitively make sense that to be killed in familiar surroundings without the preceding trailer loading and unloading etc would be less stressful.
However, as a species we do tend to anthropomorphise what we 'expect' animals to feel/think etc. Ultimately if an animal (not a primate) does not feel threatened then there is no reason for it to be stressed, so adequate resting etc after transport etc, plus quiet handling before slaughter goes a long way to alleviate the situation.
I think 'on farm' slaughter would be achievable on a small scale, but as soon as you get larger numbers then the ensuing logistics could be problematic.