I have a 16 yr old sulcata. She's had the run of my yard for years. I have a dogloo out there with a heatmat for a night box. She sometimes sleeps in there, but also sometimes sleeps underneath in the den she dug for herself. I'm done pulling her inside my basement in makeshift winter enclosures, so I'm planning to build a proper winter house. (I live in Oakland, CA). Should I make sure to leave her natural den still available to her, or can I cover it since the winter house will be much bigger than the dogloo?