Combining Hives

[Louise]

I want to combine 2 weak hives using the newspaper method.
What has been your experience with killing one queen versus letting them figure it out?

ABC/XYZ says it is not neccesary to kill one queen and that usually the queen from the top box is the one who survives.

[Michael Bush]

If you have no preference between the two queens based on race, production, temprament etc. then I'd let the bees sort it out. If you DO have a preference them by all means kill the one you don't want to keep.