Though considering they made an entire new rig for the mute swan, and didn’t even make it the star of the pack. We could see something really cool. I think it depends on what the other animals in the pack are.
Hey i'm number one rhea fan here. I also accept is a full on clone but it is also one of the few trully essential SA animals left. Most of the other important birds from SA are flying birds so i'll not counting on those. But besides wanting the rhea personally there are some reasons to believe is very likely:
1. Clone. Easy to make. Not much animation work needed.
2. Widespread, common in zoos and popular SA ground bird. So it hits a lot of boxes.
3. It is fairly requested.
4. Is pretty much the only ratite missing, so is weird is not in the game.
I personally think it will be better as anniversary animal to expand on SA base game roster but idk if we are getting another anniversary animal and it might be something else.
The swan is the only reason why i think a pelican is also likely. It will only really need to adapt the rig to fit the pelicans bill which is it's main features but would work well on the swan rig.