He will seem hungry after eating for a while because he is still in "feeding mode". Me, I'm not a huge fan of feeding boas much more than they need to maintain a healthy weight because I personally have seen a few too many fat boas that died young but thats just me. If he isn't loosing weight and has a good body condition, I'd just feed him that much. I would get him up to rats though as soon as you can. In my oppinion, a male can be fed on small rats his whole life so he will grow into them and when I get my boas on small rats, I slow the feeding down to aprox. every 2 weeks regardless of sex. The sooner you get them on rats, the less of a chance you have of getting it him stuck on mice when he is 4-5'