Well, her being shorter in length than the males probably just means she's younger than the males. But for the girth difference, it could have something to do with the prey you're feeding. Generally, when you switch to rats, you'll notice a nice change in girth. Your snakey will become a fatty in no time. I can't say if switching from adult mice to rats is healthier or not, but I have heard that rats help bp's put on a lot of girth.

And weird, my ball python is only 3 months old this coming wednesday, and she's already eating 2 adult mice a week. I'm looking to switch her over to rat pups when I can get a hold of some.