Re: brooding after winter solstice
I am not sure a indoor observant hive would produce the same climate as a hive outdoors in full sun. Considering all the factors involved I suspect a cluster inside a hive in full sun could get much warmer than on in a house at 70 degrees but no way to get solar gain. Keep in mind that bees want it more like 95 degrees. Our typical 70 ish would be on the cool side for them. It is the lower end of brood rearing temperatures and I have seen information that suggests the development of brood is retarded at those temperatures. According to observations made by Huber anyway.
As I understand it brood production does not necessarily sease. it slows down up to the solstice and then begins to increase again. I would suspect that weather and other factors also need to be considered. Colony strength which I have seen information that indicates a weak colony is more likely to to continue with brood more than a strong one.
Winter brood production is confirmed by Langstroth having found frames of brood in a hive in early February.
"opening one of my hives on the 5th day of February and found an abundance of eggs and brood. Although the winter had been an unusually cold one,..."
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.