I have a hive that is 3 years old. I treated with Apistan strip last fall. Just checked the hive and there is markedly less bees and a large pile of bees just in front of the hive dead. I split this hive in the spring and got a new queen and moved about 100 miles away. This week that hive also had a large number of dead bees in front of the hive.
Any suggestions to the cause?