I've seen those and to be honest I'm not quite sure they're big enough for chooks! My local garden centre displays its hens in one of them and they look very cramped.
The one holidayhutch has is great though - my chooks are in a similar thing, just with a nest box and a larger pen and they love it. I can imagine the bunnies would too, but it does need moving quite regularly so they always have fresh grass. I've seen them on zooplus recently.