Okay, looks like I'll just have to keep tinkering with it until he eats. I've pretty much tried everything before that's been given as advice: his hides are tight, I've shut the lights off, I've given smaller rats, I've left him alone the day of, I've heated the rat a bit extra... I haven't found something that works 100% of the time

The weird thing to me is that he will take the rat the instant it is in the cage. I've even gone to remove the rat to heat it back up and he'll grab it back the second I start removing it... He is the best at taking the rat, but the worst at actually eating it