Just some thoughts on photoperiod and thayeri hatchlings . . .
King snakes are fossorial (i.e., they like to hang out in underground cavities or deep in cracks between rocks), thigmophilic (i.e., they like to feel their bodies touching something, like the sides, floor, and ceiling of cavity), and nocturnal. For these reasons, king snakes are often "in the dark." Thus, in my opinion, photoperiod may not be as important as other factors for keeping hatchlings and juvenile snakes feeding through the winter. I just keep 'em warm and they seem to eat well through the dark days of winter. No special lights seem to be needed.
However, it is typical for my adult thayeri to slow down and start refusing meals in mid-to-late October. I don't know if they are responding to the cooler temperatures in the snake room, or the shorter days, or both, but they do seem to "know". I take this behavior as a cue to get them ready for brumation in my unheated basement. After they are set up in the basement, I cover the whole setup with a thick blanket so the snakes are in total darkness. I think there is some evidence that total darkness during brumation is desirable because it emulates the total darkness of a natural spot for brumation. In any case, that's the only time of year I worry about light exposure.
Hope this helps.
Tom
