Welp, it looks like Rocky had escaped after all. Amos recently discovered Rocky climbing around an upside-down garbage can lid in the yard as he chased after a squirrel. I’ve modified the enclosure to include some hanging lips to reduce the chance that he can climb out again, but the yard itself is well sealed too… I think.
In any case, Rocky was ravenous; he immediately chowed down on some dog food when I presented it to him.
And another piece of news: I’ve inherited another box turtle from a neighbor who’s moving. It’s another male, and, after a brief attempt at mounting him, Rocky and Humphrey immediately began a bout of aggressive bobbing and biting. They do not get along and are now separated.