House chickens usually have a cage or enclosure in the house. Some house chickens go outside to enjoy the day, like dogs that live indoors, but go outside to play and run. It's common for them to wear chicken diapers when they are loose in the house. Have you ever seen the flight suits for parrots? It's the same basic design. Flight suits come in sizes for birds from budgies to macaws. My African grey is potty trained, so he doesn't wear one. He holds it until he's back on one of his play areas or in his cage.
I've heard of a pet rooster that would go peck on the door when he wanted to outside and poop, but there hasn't been much success in potty training chickens at this point. I think mostly because people haven't tried. I always read that chickens couldn't be potty trained because they couldn't hold their poop in. Well, I'm not sure I believe that, after living with chickens. Broodies and roosting birds hold it in. Hens waiting to use the favorite nest will pace and become annoyed while they wait, but still hold that egg in until they get into the nest. Mine never poop on me, when I'm holding them, but will poop after they are put down. I think there is at least a minimal ability there.
Until someone does it, many things are thought to be impossible.
