I thaw under a heat lamp in the snake room. The rat smell circulates among the snakes (I can't smell it) and I start seeing heads poking out of hides after about an hour. After two hours, every hide has a little head sticking out. Generally, everyone eats as soon as I put the rat in front of them... instant strikes. I'll hit the rats for any problem feeders with a blow dryer but it's usually not an issue.
If the snake doesn't take, I'll remove the rat, wait a few minutes, hit again with the blow dryer, and re-offer. If it still won't eat, I'll leave the rat overnight and it's always gone. I have 3 live feeders who wouldn't convert to f/t until I dropped the rat and shut the tub and left them alone. They are perfect eaters now but it seems like they just wanted some time in the dark to check the f/t out before accepting it as a food source for the first time.