I'll get into the details of building the piggery barn later, but thought I'd take take the opportunity of a rainy morning to share with you how we filled the pens themselves. It's an interesting process.
One must first construct a pen in order to fill it.
We used cinders to fill in the corners up to the tin sidewalls, then the pen was lined with a woven geotextile plastic groundcover-like fabric. This is to keep the rocks and cinder from puncturing the actual liner, which is a thick woven polyethylene waterproof material. Using a waterproof liner like this is not part of the CGNF method. Ideally there would be direct contact with the soil. However in the US, there is great concern over groundwater pollution, so hoops must be jumped through. Our piggery is the pilot project for using something other than concrete to line a deep litter system. If this works, and we have no doubt it will, then it will open up a less-expensive alternative for backyard farmers. All this has come about with the help of Mike DuPonte from the University of Hawaii-Hilo Agriculture Extension Department.
On a fine early February morning, several folks from our local Natural Farming group came by to help with filling the pen, and to learn how to create the various layers needed for the microbes to thrive. Very hands-on and always more fun with friends to help!
First, we spread 3-4 inches of red Hamakua cinder-soil, and topped that with 1 cubic foot of biochar.
Pen maintenance is easy. We rake the floor smooth every morning while the pigs are feeding. For a while, more IMO4 was sprinkled weekly over the fresh manure to help it break down more quickly. This is no longer needed because there is enough microbial and fungal life in the pen to do the job.
That's it! No smell, very few flies. Contented, happy, healthy pigs. That's what it's all about.