I am looking for an answer to this question too. I have 3 8-9 week old piglets and want to put them in the pen with a Sow, she has had piglets herself but these aren't hers. I only have one pen that's 16ft x 32ft. I had put one of the piglets in the pen but had it separated from the sow by a fence. The sow seemed to me to be a bit aggressive towards the piglet, she was grunting a lot. The piglet wasn't making any noise at all, just seemed to sniff a lot at the sow through the fence. I currently have the piglets in a temp pen out of site and sound from the sow. Would the piglets be ok if I put them in the pen with the Sow?