Hi, Hebber
Killing out % is the % of the animal's liveweight that is useable carcase i.e. after the insides and stuff are removed.Looks the KO% of poultry is about 78% - this is high compared to other species. I think the KO% of cattle will be much less - maybe 50%, because of the huge amount of guts that a cow has.
If Andrew Sharp reads this, he'll know because he used to be a butcher and they know thsi kind of thing!!