Re: Combining hives with screen
Saltybee is correct. More on the concept of multiple laying workers:
There are always multiple laying workers even in a queenright hive
"Anarchistic bees" are ever present but usually in small enough numbers to not cause a problem and are simply policed by the workers UNLESS they need drones. The number is always small as long as ovary development is suppressed.
See page 9 of "The Wisdom of the Hive"
"Although worker honey bees cannot mate, they do possess ovaries and can produce viable eggs; hence they do have the potential to have male offspring (in bees and other Hymenoptera, fertilized eggs produce females while unfertilized eggs produce males). It is now clear, however, that this potential is exceedingly rarely realized as long as a colony contains a queen (in queenless colonies, workers eventually lay large numbers of male eggs; see the review in Page and Erickson 1988). One supporting piece of evidence comes from studies of worker ovary development in queenright colonies, which have consistently revealed extremely low levels of development. All studies to date report far fewer than 1 % of workers have ovaries developed sufficiently to lay eggs (reviewed in Ratnieks 1993; see also Visscher 1995a). For example, Ratnieks dissected 10,634 worker bees from 21 colonies and found that only 7 had moderately developed egg (half the size of a completed egg) and that just one had a fully developed egg in her body."
If you do the math, in a normal booming queenright hive of 100,000 bees that's 70 laying workers. In a laying worker hive it's much higher.
USDA Zone 7A Elevation 1400 ft