Suzanne - thank you very much for your comprehensive reply. I think I understand it all a lot better now.
When the fallen stock people shoot a sheep for us I am pretty sure they don't pith. Does this mean there is a chance the animal might regain some sort of consciousness in the wagon?
when a knackerman was at ours, i noticed a sheep was still breathing in the back of his lorry. he said he hadnt shot it it, just picked it up from a farm apparently already dead, but know he realised it wasnt dead, he would shoot it when he was away from my farm. he said his boss would go nuts if any animal was taken back not dead.