1. Open iTunes on the desktop.
2. Click on Movies.
3. Click on List.
4. Find the movie you want to watch.
5. Go to the iTunes Extras listing immediately beneath it.
6. Click on the iCloud download icon

   

   How to AirPlay iTunes Extras on Apple TV

7. Once the iTunes Extras have finished downloading, double click to launch the iTunes Extras menu
8. Select the video content you want to watch and double click on it.
9. Once the video content starts playing, click on the AirPlay icon and select your Apple TV. (Apple prevents the screen capture of DRM content, so ugly photo we get!)
10. Watch your iTunes Extras on your Apple TV. Finally. 

    

    Tips to AirPlay iTunes Extras on Apple TV

Yup, that's what it currently takes to watch iTunes Extras on the Apple TV. Hope this tips how to AirPlay iTunes Extras on your Apple TV work for you.

Source : http://www.imore.com/how-use-ridiculous-workaround-get-itunes-extras-play-your-apple-tv