Now that it is warming up, Opo and I are having a disagreement about letting him sleep in his burrow. It gets into the low 60's at night. I had it blocked off all winter. The way I had it blocked off. Opo finally figured out how to get in. I had to trick him last night to get him out. Sooner or later he will figure out my tricks. He is around 60lbs and I was wondering if it's still a little early. To allow him to sleep in the burrow at night?