Just seconding what Deborah said. All my slow starters go on her plan (as of a few weeks ago) and they have all taken except one (but he has only been on the plan a week).
The reason for my post (other than to say Deborah's plan works) was to add that I have a young male who will only eat in total darkness. Blind all the windows, turn off all the lights, not even as much as a flashlight in the room (the incubator fan light is to much), then he will eat. He's been on rats for almost two years and eats 60 gram rats but it must be as dark as we can get the room.