Some people don't agree with this tactic, but several years ago I ended up with a problem feeder and I ended up with a feeder I had nowhere to put so I put two female gerbils together and popped it in the vacated cage because I was late to work. I retried the feeder that night straight from the gerbil cage, and instant strike.

For that animal I was extremely successful switching her to frozen thawed as long as I rubbed it in dirty gerbil bedding.