>Has anyone else used three deep hive bodies for brood?  Does it have any
>merit?
        At  the risk of raising the obvious, isn't this approx. equivalent
to asking whether queen excluders are good?
        I have seen friends running  -  partly for glee  -  hives of 7 or 8
full-depth boxes on a big flow of manuka nectar, with no queen excluder (I
don't mean to restart that discussion, but some beekeepers dislike them).
All those boxes are, in a pedantic sense, brood boxes  -  the queen(s)
*can*  get into all of them; but in practice brood doesn't appear above the
bottom 2 or 3 which are left year-round in our temperate climate.

R