Rowie, I've now twice introduced test frames in my colony, but they did not draw out queen cells although I'm almost 100% sure they're queenless - so I asked for advice and was told it's too late for test frames to be accurate; that they might not draw out queen cells even though they're queenless. So bear that in mind with your test frame. I'm now going to unite my colony with another using a queen excluder as DR suggested (and keep my fingers crossed).
Kitta
Bookmarks