Pot Bellied Pigs/Adding a new baby pig to household
We have 1 one year old potbelly pig. We recently brought home a nine week old pig. Our one year old (Sue) has become aggressive towards us whenever we get near the baby(Zeus). She has become a mama pig to him and he has even got her to start producing milk by rubbing on her belly. Her aggression has not lesson in the month we have had him. She won't even let me pet her without growling at me or any other family member. What do we do? We love our Sue but I am worried she might try to bite one our kids.
This is an usual situation. It's normal for pigs to bond closely to each other. But, they rarely abandon bonds with their human companions when a new pig is introduced.
If she's expressing milk, this is clearly more than just grumpiness on her part. It's not normal for simple stomach stimulation to cause milk production, and practically impossible for this to happen with a spayed female. So my first thought is, spayed or not, she needs to see a vet.
Male piglets are fertile at 6 weeks old. More than one male baby has accidentally impregnated his momma while he was still nursing! So, if both these pigs are intact, she may already be pregnant.
Momma pigs normally wean their piglets at about 8 weeks of age, and almost always by 10 weeks. So, if your piglet was weaned naturally by his Momma (not pulled early) and 9 weeks old when he came to live with you, his nursing behavior should have mostly stopped on it's own. If he was just 5 weeks old a month ago and is 9 weeks now, the behavior should stop on it's own fairly soon. If it does not, you may need to separate them.
In fact, you might need to separate them anyway for resocialization. Ideally you'll need to separate them only for a short while a couple of times a day for training and socialization.
Spend some one on one time with each pig individually. Make piggy practice some simple tricks for treats. If your girl gets upset when you try to take the boy out by himself, take her first, then take the boy out before returning the girl to the empty pen.
But, if one at a time turns into a big problem, you might need to separate them completely, resocialize both of them separately, then finally put them back together again. It is a time consuming process, and chances are they will fight when they are reintroduced, but the end result will be safe, tame pigs.