If a colony has say 40,000 bees and the average life span is 6 weeks, then roughly 1,000 bees a day need to be born, and 1000 a day will die.
In the cool season all that slows down quite a bit but still it continues to some degree.
If you live far enough north to get snow, you will see the results quite easily as they land and die on the snow. On local forums (is there such a thing on the net ... maybe that's an oxymorom ) up north beginners like me get alarmed when we see the bodies in the snow. Everyone with years of experience assures us it's quite normal.
"hobby farm" is an oxymoron