The Sorting Room! (Thanks to the abyuse.com forums for the idea!)
Divide a room into two parts with the barrier tool.
On one side, put beds, a toilet, an auto-feeder, and toys; this is the pet yukkuri side.
On the other, put plates of garbage out; this is not the pet yukkuri side.
Then, generate 4-6 yukkuri (I like to go with koyukkuri, so they'll play with the toys). Polite yukkuri go on the pet yukkuri side; shitheads go on the other.
Instead of using "clean whole yukkurium", when the polite yukkuri poop, toss it over to the other side.
Watch as the shitheads freak out at the barrier! Listen as they bitch about the bad food and Mister Poo-Poo! Watch them reproduce anyway, despite the living conditions!
Stressed? Pet-pet one of the polite yukkuri, and watch them smile! Treat them to orange juice and enjoy their gratitude!
Or chop the hair off a shithead! Smack it around a bit to remind it who's boss! Deprive them all of food when one of them calls you a slave! (They don't learn, of course, but when do they ever?)