Moa were some kind of retarded looking dodos that lived on Reach. During the fall of Reach, these freaks of nature were hunted by Noble team and the Covenant and were officially owned when Reach was roasted. It is unknown if any of these things survived. If so they would've been put in freak shows all over the galaxy being tortured by Grunts throwing rocks at them and Brutes raping them.
Moas too, but that was to get achievements.
Moa were hunted by Noble Team during the battle for reacharound as it was at the time Christmas and 6 felt like some turkey for dinner. They later found out they could have bought some down the road and were attacked by greenies for causing them to become extinct.
They are believed to be related to jackholes due to their similiar turkey look. Also see the below images.