well i have a 6 month old female bp (length unknown) and 2 of those hide boxes (both smalls) and she's JUST starting to be a tight fit in them with an empty belly. with a full belly the hide boxes will sit ontop of her but i've heard they like the tight fit and that they dont mind lookin' like a turtle at times. i will warn you though the size of the smalls will throw you off big time the first time you see 'em. they really do look tiny but my girl fits in 'em so...hey i figure she aint complainin' so it MUST be ok for now huh?
i think i'll upgrade to mediums soon though ...