I'm sorry, but I cant find the thread where I promised I'd post the results of this experiment I tried earlier this summer.
I attempted to requeen 12 hives using queen cells without removing/ killing the old queen 1st.
The sucess rate was 8 out of 12.
However, 2 of them squirted up though the queen excluder ( God knows how.....are they smaller when just hatched, before their wings harden? ) To form double queen hives.
A few folks had expressed intrest on what would happen, so here it is as prommised.