Pig pens are the most subjective crazy annoying things I have ever read; From recommendations from Texas Tech University to books to eBooks to Pliny the Elder. So far, I have a 25 x 100' pen (7.62m x 30.48m) I can easily make another with out working very hard at the moment that is 50 x 25. (15.24m x 7.62m) for 2 piglet size Berkshires that I plan to see pregnant with a litter in these 2 pens till I am physically able to do another 25 x100(7.62m x 30.48m), or are the first two enough for 2 potential sows with litter the first year? Additionally, the 1st pen, that is 25 x 100 is semi forest in rehab and over grown blackberry with prairie area in rehab. South of this is a swale on contour with a jumbo chestnut, more coming as life allows. When I am physically able I will have the pigs go over the swale to another pen that would be 25' or wider x 100' that is a more forested in search of rehab area. The second possible pen that is 50 x 25 is most prairie / blackberry. A jumbo chestnut will be in this area that drops into this pen as well. Both areas will be getting oak for acorns as well in the future when $$$ allows. What is your opinion and why for the size pens I need for the 2 Berkshires?