How are you offering the frozen rats?

Some like you to move it around and some like you to toss it in. Some like it with the lights off at night and some like it in the day..

The worst snake I have takes 30 minutes of me putting on a rat puppet show in near total darkness.. I put in a live rat and its gone in 10 seconds.

It can be tricky to get them feeding on F/T. Also have you tried a fresh killed rat?

Richard