My 14yo daughter has a rabbit. It never went outside much until a few months ago. She has it litter box trained and it is amazingly clean! He's so funny to watch him hop around the house, up the stairs. Over the winter I thought about converting the old 8' X 16' sandbox I had built with a roof years ago, into a hutch for him I figured he could stay outside and play during the day and come in at night.
When I was just about done with it, I realized that I had done everything I needed, to make it ready for chickens as well! I had talked about getting some chickens for years now - so, here I am! He gets along with them fine, and the chickens drink out of his water bottle as well. Thats when I realized that getting nipples for the birds would be a good idea. (that and not having to change the water every 4 hours because they poop in it).
I ordered some from Neil Grassbaum here on the forum.............they work AWESOME!!