If you are worried about burrowing don't buy a boa.. Hahahaha.. I have some BP's that do it and others that don't.. Seems like you have got good advice from other replies and things that you should check. As far as a BP laying still I don't think any of us can help you there.. They aren't the most active serpents to say the least.. With them being nocturnal you will likely very rarely catch activity periods.. To close things out, nothing you have in the post would concern me personally as long as the husbandry is accurate..