I have a late 09 female cinnamon that's a very sporadic feeder. Sometimes mice, sometimes rats, sometimes nothing at all. She's 625+/- grams. It's frustrating, but at the same time, I don't sweat it though because she doesn't lose weight...or anything significant.

I have a couple mouse/ASF only as well, but consistent feeders. Though not crazy about mousers, I don't get all up in arms over them either since I breed all my own mice, rats, and ASF's. I have been getting tougher on my younger snakes though, and more persistent in switching them over to rats.