It's so female dependent. You will have better luck if you use rats, if you offer at least once every 10 days, and if you offer multiple food items.
But I have one 2010 girl that has been skating by on 1 mouse a month for two winters. She won't look at a rat sideways, and she's barely 900 grams at 3 years old. I also have one 2012 girl that is 600 grams and just polished off 4 rodents last night. FOUR. Rat pups AND adult mice. It wouldn't surprise me if I wind up breeding both of these girls for the first time in the same season.