My friends dad is a multigenerational farmer in Midwest and he farrows in field using large rd hay bales. the sows create cave nests by eating into the bales and farrow in there. He has had good success with this. Sows are ringed to prevent borrowing under the fence. results in healthier pigs and less farrowing fatalities I hear. Have not seen the set up, but this man is a very good farmer, president of his sustainable soil conservation or some such. The farm I worked on was a high end horse farm but we serfs snuck garden and livestock for ourselves here and there and the landowner didnt care as long as she could not see ti. We placed round bales on the far, high side of the composting piles so they could use the warmth, and then when done folded the used stuff into the pile, easy breezy. Sow ran in the woods rich in mast of hickory and oak, apple, etc. Worked for about 5 years then our butcher guy retired and he was our king pin for this, so we stopped the pork production. If you have a big enough compost heap, there usually is a wet side and a dry side because of scraping it up with a loader, so the bale is placed near the dry side, cooking side and the pigs will wallow in the wet side and help mix it. Should fence them in, we did not and I am sure that is illegal.
