I recently purchased a gram scale so I can weigh my Ball. He's a 7 1/2 year old male (I think he's male) and he's about 4.5 feet. Anyway just weighed him for the first time ever and he is 1537 grams. My question is, is that a good healthy weight for an animal of that age and length? He eats a rat every 5 or so days. Would I need to up the feeding or is he good?