How often to feed female to help get them up to size?

[grcforce327]

I have 7 females currently. My 4 biggest girls are around 550g and 650g. I feed twice a week about every 5 days. they are all early 2012's too. I alternate between two adult mice(24-28g) at the first feeding to one wean rat(30-45g) for the second. Is the food size adequate, and am I feeding often enough? They're all still very interested in eating despite being at the so call feeding wall.
How often do you experienced breeders feed?

Looks like you have some slow growers!
This holdback phet spied girl hatched aug 27th last year. I see a possible wall soon.