Really is dependant on the snake and it's feeding habbits - just like people some will bulk up and some tend to be slim and then there is a whole lot in the middle. If he is eating the appropriate sized food item regularly then there shouldn't be an issue. Perhaps you can post a photo.
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Tosha 
"Nihil facimus sed id bene facimus"

10.35.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Anakin Skywalker)
0.0.1 Green Tree Python (Verdi - yeah I know but my kids love the book)
0.1.0 Bredls Python (Smurfette)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Desert Tortoise (Pope John Paul aka JP )
2.2.1 Fish (1,2,3,4)
0.0.1 Lizard rescued from feline
0.0.0 frogs rescued from pool skimmer