It takes a while for a new bin to establish a healthy micro-herd. One month may or may not be long enough. The reasons the food seems to be lasting in the bin are the lack of microbes and the small number of worms. Give it time.

If you want to give your bin a boost, try tossing in some partially decomposed compost. When I started my bin, I found a spot where a neighbor had been tossing his yard trimmings over the fence. I dug down until I found dark, crumbly organic matter. I used this to introduce microbes to the bin. My worms were very happy about that.

Your worms are probably headed to the bottom to find the places where there is more moisture. Newspaper tends to dry out, so the worms may be avoiding the dryer top layer of newspaper.

No need to fluff. Just watch the moisture content. If the top is drying out, spray it lightly with water. If you bury food waste in your bin, rather than layering it on top, you will fluff things up enough when you bury the food.