Feeding has been shown in studies to be from 4 to 8 times more efficient than chasing natural food.
Could you please expand on that statement providing examples of what you mean by that and findings you are referring to?
If we are talking LMB eating fish as natural food we need to take into account the dry weight and when we do the difference isn't all that great. The moisture content of whole fish is about 75% of the wet weight and if an LMB gains 1 lb on 10 lbs of fish then the conversion is 2.5 lbs dry matter to 1 lb gain LMB. To be sure, LMB don't have to work for feed but I don't see the 4 to 8 times more efficient than natural food from expending less energy.
