My DH & I use to volunteer at a botanical garden and were allowed to bring home 'spent' potting soil, plant clippings, etc. I would put it all under the domestic bunny cages and let the banty chickens have free access to it. They did all the turning and mixing for us. In a few weeks we had blk. gold to use in the yarden. Nice and loose because it was largely based on commercial potting soil which is mostly peat and vermiculite. I tried to get some of the dirt underneath mixed in but often had to go elsewhere on the farm for 'real dirt'. There were usually tons of worms in there too. Too many for the poultry to eat.