You can't keep pigs in the Palmerston North urban area, which is anywhere zoned residential or village in the District Plan. Rules apply if you want to keep pigs on rural land, including requirements for maintaining pigsties, tanks and troughs, and storing pig food. For more detail, see the Animals and Bees Bylaw.
Keeping stock in the urban area is allowed as long as you meet the conditions outlined in the bylaw. Stock should have an adequate and appropriate living environment for their species, and owners must provide for their companionship, space, shelter and shade needs.