it took mine a couple weeks to eat when I get them so I just wait a couple weeks now when I get a new one. They poke around the enclosure to just check boundaries and how far he can go. I feed in the same enclosure but I don't leave the rat overnight because once it gets to be the same temp as the ambient air he can't see it. I thaw mine with hot water to make them soft then dry them with a hair dryer to make them 100 degrees....it seems to work pretty well for me (except the one I have thats finicky and doesn't eat all the time.)