Lorraine will do the same thing when she is ready to go to the next size. She did the same thing when she was on rat pups, she refused 2 weeks in a row, week three I had thawed out both a pup and a small rat; she turned up her snout at the pup, so I took it away. When I started to put the small rat in there, I barely had time to start the corpse dance, before she hit it and coiled. She knew she was ready for the change before I did.