All the houses do pretty well for setting up auto-farm pigs/butterflys. Just plonk down your animals and away they go.
Where animals pens come in handy is that it keeps them away from your trees and crops. It's a pest clicking your crops with all these animals around, and pigs eat any produce that your trees drop spontaneously.
At the moment I'm in the market for the 50k homes, though I've got a very nice Asian themed cottage right now with I'm loathe to give up. But I really want the extra crops and animal pen... sigh, so many decisions for a Glitch.
SEAK on the Bartle Test
You are stood on a narrow road between The Land and whence you came. - MUD1