Another thing you could try is double the feedings. I had a female come to me from a friend that was way under weight and was only being fed 3-4 mice every 2 weeks and was 4 years old and just over 4 feet. I got her on small rats and then I would take and give her one small rat and follow feed that, take the nose of next rodent put it to the rear end of the one in the snakes mouth, and feed it a rat that was a little smaller. After a few months she had gained a lot of weight, almost 3lbs, and was over 5 feet. I did this til she filled out quite well, maybe a little fat, and then slowed down her feedings to every 10 days but was giving her rats just a tiny bit to big. She is now on one XXL rat every 2 weeks and is in excellent health.