Hmmm . . . this is interesting, Emu Hugger. My emus don't spend time playing in the manner you describe.
A local made an interesting observation. He said that the wheat that I feed my birds they get about a double handful each per day is very high quality food for an emu. He noted that you can tell the difference between an Autumn pile of emu blessing and a mid-Winter pile of emu blessing. The winter model is almost liquid because there's little solid food in Winter. Conversely, in Autumn, there's lots of seed in the wild grasses, and that's protein. My birds spend hours and hours and hours grazing every day. Indeed, in Winter, almost robotically. I really wonder if your birds have more time to play because their food is so much more solidly nutritious. Do your emus spend a great deal of time grazing?
Supreme Emu