I believe they do have to sleep, hibernate, through the winter.
I have a large female who produces between 4 and seven eggs a year. I bring her in the house for the winter and keep her in the basement, every three days or so I put her in water for an
hour or so and she takes a big drink and goes back to sleep. I do this to keep her from dehydrating. I have four adults and 5
babies ranging in age from 5 years to 5 months. I keep the 2 year
old and the two 5 month olds awake all winter keeping them moist and warm.
Hope this helps some,
Alan