This seems to be a home sharing bug. I have the same propblem with iPad Air. Home sharing from mac host works but only Movies, Home Videos, and music work. TV shows, while shown as a share on the iPad Video app, will not show.
My solution is go group change the "Media Kind" in iTunes from TV Show to Movies or Home Video. If you are not particular about how your files show in iTunes, this works in my case on my iPad.
It is also possible that if you are encoding these movies you may be using the wrong settings for Apple TV. ATV is very finnicky. The only encoder I've gotten to work consistently is Handbrake.