Maybe she's due for the next size up? Depending on her size she may be ready for a little more in her meals and was probably just hungry and ready to go.
Especially since you said she wrapped his arm? I'm thinking that's a decent size and ready for a small rat over a mouse.
If you haven't already, a good idea is to pick up a scale and weigh her. Typically we feed around 10% of the body weight as a meal every 7-14 days depending on factors like age, sex and if they are being bred.