When I emptied mine at the beginning of March it certainly got the approval of the plot robins!
As you posted a while ago, you may or may not have found any problems with egg shells by now. I stopped putting these in the bins because they attracted rats. Not everyone finds this, I know, but the shells were being dragged out of the bins by the enthusiastic rodents. Baking the shells in the oven before adding to the bin might solve this, but when I've baked them, I crush them up and save them to sprinkle around as a slug deterrent.
If I start up a new plastic sealed compost bin, & just add in the chicken's poo, the newspapers we line the nesting box with & the odd bit of grass they haven't eaten, how long will it take to break down??