The Show Pen will store both sets of animals for you to show off to your neighbours and be upgradeable to store endless amounts of them.
As usual it'll start with a popup...
Once built up you can store a few of your Pigs and Sheep to begin with, then gain more space as you complete more builds. You can also upgrade as many times as you want when fully built to add 10 spaces each time.
Once inside the Pen will show you all your pigs and sheep and allow you to click on them to get a full guide on how heavy they were, who the partner was and what it looks like. You can also remove them and place them back on your homestead.
As well as the building we'll see two new animals, one of each type...
...and two collections!
So get building and best of all, get storing!