I built my own TBH this spring and got bees in the middle of April. The colony is doing great they have built quite a bit of comb and have come fairly close to filling the hive. To my surprise they swarmed yesterday. It was perfect because I had another hive waiting for them and I was able to capture them quite easily. But, from what I understood they usually don’t swarm the first year… Is this true? The bees had 3 or 4 empty bars they could be spreading into and they still swarmed. I am worried that I will be left with 2 weak colonies instead of one healthy colony. Should I be concerned? Also any explanation for why they swarmed?