are you sure about that weight? if so, at a year old, I think she has been significantly underfed for a long time. From the pic, the rat does not seem to large to me but I will let others chime in on that. I'm not sure about eco earth but I'm sure a little sticking to the rat won't bother her much, they do eat in various environmental conditions in the wild.

I don't know where you got the info to feed you bp small mice from but you should check the forum for more info on feeder size by age.