When can I start leaving them outside to live? I built a place for them outside a.nd would like to start keeping them outside. Just dont know if I should wait till there older
My general rule of thumb is an hour of outside time per inch of tortoise. Once they reach 5-6 inches, I start leaving them outside most of the day when weather permits. I move them outside full time with a heated night box once they hit around 8-10 inches. In Tucson, you'll need to let or help the tortoise burrow in summer. That is the only way to escape the scorching summer heat. Then in Fall, you'll have to block off the burrow and make the tortoise start using its heated night house for shelter until the consistent hot weather returns in May or June.
You measure the plastron. I put a tape measure against a wall and set the tortoise with their face against the wall. Then I look straight down over the tortoise at the tape measure. Like this: