One great thing about Balls is their ability to recover quite quickly from long-term malnurishment if given the proper conditions and food. We took in a 5 year old female that weighed under 1000 grams about 2 years ago. She layed 8 eggs last June at about 2500 grams. Give her a proper sized meal once a week, and she will grow very quickly compared to what you have seen.
-Evan