> I've never put pollen sub on a hive that had adequate access to pollen. 

To put it politely, some folks think that spending money on a problem can't be a bad thing. I presented on the topic of bee nutrition at WAS in Boulder, and condensed the talk into an article which appears in the December ABJ. One of the points I make is the failure of pollen supplements. 

I discussed Heather Mattila and Gard Otis' work, the title explains it:

"Manipulating pollen supply in honey bee colonies during the fall does not affect the performance of winter bees." Mattila, Heather R., and Gard W. Otis. The Canadian Entomologist 139.04 (2007): 554-563.

And, Gloria de Grandi Hoffman. Colonies fed protein supplements did worse than those on natural forage:

"Honey bee colonies provided with natural forage have lower pathogen loads and higher overwinter survival than those fed protein supplements." DeGrandi-Hoffman, Gloria, et al. Apidologie (2015): 1-11.

They state: "Feeding colonies PS in their current formulations does not appear to remedy problems of poor nutrition or reduce colony losses. In our study, we lost 30% of the colonies fed PS (protein supplements)."

Finally, 

As demonstrated in other insects, diets that are optimal for growth are not necessarily optimal for immunity. Thus, colonies that are building in the spring may require nutrients geared toward growth while in the fall when brood rearing is reduced and colonies are preparing for overwinter confinement, nutrients needs may be directed at supporting immune function. 

DeGrandi-Hoffman, G., & Chen, Y. (2015). Nutrition, immunity and viral infections in honey bees. Current Opinion in Insect Science, 10, 170-176.

One thing is clear, there is no substitute for abundant, diverse natural forage. Not all locations will have these features. Some locations are simply poor for bees, and feedlot style beekeeping may not work all that well, if healthy bees are the goal.

PLB

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