Something We Never Said in Porkopolis

I came across a new expression today, by way of The Night Watch (which I'm enjoying very much).

A couple of the characters were sharing an orange (which was an extravagant birthday gift during the rough times of this week's market crash WWII).

So Helen broke the skin, and peeled the orange, and divided it into pigs.

Pigs?!?

Anybody every split their orange into pigs? Did your mom? Did your grandma? Anybody know the etymology or what US or UK region it might have come from?

I did a bit of Internet research and didn't come up with anything.