(1) joking aside, please don't monitor logs like this. instead, treat your employees like real human beings and understand what they feel. not only is it more efficient than trying to reduce complex humans to a few "metrics", but it will allow you to detect more than just "boredom".
(2) if you're thinking "how can they be bored when everything is so busy and there's so much to do?" maybe you are one of those over-managing bosses that doesn't delegate enough and, surprise, ends up running around being busy while everyone else is bored and lacking responsibilities. [i considered posting this anon, but it's not aimed at my current employers and, if you know me, you'd know i'd have said it to their face if it were...]