Single post in A Beginner's Guide to Happiness and Fields.

Flying should work. So should ice and water. Rock will be neutral since it's resisted by ground. It will lose happiness very rapidly in ground since flying is immune. If you put it in flying and nothing changes, try taking it out and putting it back in - there's an uncommon bug where that happens. But it also won't gain happiness while busy, like in the daycare or scouring, so make sure its status is "idle".