Non-laying queen swarms

This is an odd one.

I had a nuc which was full of bees and a queencell. Queen emerged but over 5 weeks went by and no eggs. (Her two sisters started to lay but after a good period of time as the weather had not been good enough for mating I assume). The bees in the hive were calm and there was a circular patch of polished cells on the three central brood frames so I was comfortable that a queen was in there although not seen.

Last week I put in a test frame of eggs. Definitely just eggs on new comb. The next day the colony swarmed and half of the bees went. (I was at work so couldn't even try to get them). On Saturday there were queencells being started and the bees were fractious as if there was no queen. On Sunday I seived the bees through a queen excluder to check for a stray queen and found none.

My theory is that whilst the non-laying queen was present the bees were happy. However as soon as there was a chance of replacing her she cleared off - or was pushed.
Does this make sense ?
Are there any other possible reasons?

Adam

Hi Adam,

Very strange. I have heard that a new queen will wait until all the brood from a previous queen has hatched before coming into lay. I have also experienced getting a new queen to lay by stimulating feeding the nuc. It may also be the new queen has not mated 100% for some reason or still may be a virgin.The fact the bees were calm and also swarmed indicates towards a queen being there.

Jimbo