That little, they can be just using nearly everything for growth. If she's passing urates occasionally, then she's not obstructed (you can also gently feel along her body and check for any lumps if necessary). My 2-ish year old bp only likes to poop about once a month. He did usually go about once a week when he was little, but he also had a long stretch or two without it, particularly at the time when he outgrew his prey and needed bumped up.
You know, I haven’t found any urates either and she doesn’t seem impacted... is there a remedy for that if so?