This morning, the low temperature was 35 °F and I found chilled drone brood at one of the hives. On the landing board, you can see a range of drone development by way of eye color...no color, pink, purple then black. On the top edge of the photo you can see that the bee cozy insulator is still on.
The hive with chilled brood has a temperature measured at the inner cover notch of 84.5 °F. It's sad that this hive became out of sync with the number of adult bees and are not able to keep the periphery of the brood chamber warm. The next hive over measured 77.5 °F at the inner cover notch and is found without chilled brood.