I always feed live, but at work i have to feed frozen thawed. Usually as long as the prey is warm enough, make sure it's warm so use a hair dryer or very hot water to bring up that temp so the snake sees it ASAP.

As long as it's warm enough and they are scared to eat it when put in their face, leaving the tank for about 20-30 minutes will give them enough time to calm down and get to business. If they are loosing weight and feeding is not happening, then, only then, do you consider other physical measures.