I have many tote type bins. I use 10 gallon totes, as the 18 gallon ones are deeper then they need to be and get really heavy. (I think you are using shredded newspaper for covering the food.) This paper will disappear as the worms will consume it, and needs to be added to as necessary. Just a thought..you might want to try KSlocum's screen method for harvesting castings. That bottom vermicompost will compact and the worms will be moving up. In a bin that size it will get very heavy before to long.

Keep in mind that if the worms are happy and active all the way through the material, then there is no problem. Unless the worms say something is wrong, nothing it wrong! ::grin::

As the worms process the bedding and feedstock your bin they reduce its volume; some of the material goes into the worms, much is off-gassed as CO2, much goes into the bodies of the other organisms, both micro and macro, that reside in the system.

When using the pocket feeding management method the general recommendation is to bed the bin all the way to the top with dampened bedding and harvest the system when the total volume of material has decreased by half and the bedding is no longer recognizable. You bedded yours only half full initially, so if you find that you've had 50% volume reduction and the bedding is pretty much converted to castings, then harvesting is certainly a good option (and the window screen method would work well at this point).

As to turning or fluffing the bedding, while doing so is unlikely to cause major trauma to the worms, the worm activity suggests that it is not necessary. Were the worms climbing the walls in search of O2 or were they absent from the lowest areas, which typically indicates conditions in that area that are not favorable to them, then you might consider digging into the material. As they are not indicating a problem, however, taking any action is unecessary. You know the old adage; "if it ain't broke, don't fix it!".

Kelly S