I am thinking a hatchling and I live in Pheonix,Arizona.So, you said you have a temperature controled outdoor area, do you by any chance have a pig blanket or CHE?Tom said:What size tortoise are you getting and where do you live? My strategy is to have a 4x8' indoor enclosure. This lasts them for their first year and half or so, when I move them outside full time. They normally hatch late spring or summer. I keep them inside for their first winter or two. By then they are too big to be inside all the time. By the time they are around 5 or 6" mine are outside all day everyday, weather permitting, and they only sleep in their indoor enclosure at night. Once they get 8-10", I move them into outdoor enclosures with thermostatically controlled heated shelters.