Stephen,

Your diagnosis sounds logical.  They can't raise brood unless there is food, even though the queen is laying.  Additionally, I suppose they are  just cannibalizing the young brood due to the same cause.  I'm feeding heavily and will let you know what I find.   Thanks for the suggestion.

Every year I have one, or occasionally two, hives that have a "failure to thrive".  The one this year has a new queen, great egg/uncapped/capped pattern, no trach mite or k-wing virus symptoms.  No foulbrood symptoms.  Relatively low mite count.  Don't seem to be being robbed.  There just seem to be fewer and fewer adult bees with the stores are also diminishing.  Anyone else experiencing this?  Any ideas?

In years past I baby them along through the summer then in 100% of the cases,  they are winterkill and I replace them the next spring.