Originally posted by HarmlessYoda:

I have 3 separate pens for pigs, the only time a pig "gets out" is when they give birth to a baby piglet with their rear end up against the fence. The piglet then appears on the wrong side of the fence which eventually means I end up with tame pigs roaming around inside the rest of my base instead of just in the pen. Not really a big deal.

it's not a birthing problem for me. I only had 2 pigs left and they both got out. I'm also not using fences at this point. its a big hole in the ground with floors over the outer edge to keep them from body piling out. i'd share a picture if i knew how