Ideal large flightless bird for domesticated cattle
So, just to be clear, when I mean "giant birds", I mean the families that presently consist of giant flightless birds (think moas, emus, ostriches, etc.) - the ones that came up with roughly similar body plans due to convergent evolution.
Given that we're using a large flightless bird (at least the ones which have existed), which one would be ideal to domesticate, using genetic engineering/selective breeding, with the goal of creating cattle? For now, we're just going to ignore whether this is a good idea or not, and beyond what motives a group or individual would have for doing such a thing.
To recap, ideal large flightless birds domesticated* for cattle purposes,
(Mild) Genetic engineering is a viable solution to make it feasible (if that wasn't clear before, eg modern knowledge and capabilities with regards to technology(genetic engineering technology and capabilities)
Presume any extinct birds are "resurrected" in identical to near-identical genetic forms, and then mild genetic engineering is applied from there.
Any form of large flightless bird would be allowed regardless if they're currently extinct or not
Are raising them for meat and eggs
Doesn't matter if they're extinct or not(currently)
Were going to pretend I had remedied that some people had domesticated Ostriches AND Emus, and restate the question as any potentially large flightless birds which would be better suited for cattle roles
Note: Genetic engineering isn't magic. It takes a large amount of time and energy to make minor changes to an organism. You can't use an animal as a template and make it from scratch, doing such a thing would probably take at least 20 years. Consuingly you can't really use it to make the "ideal" animal with goal X in mind, just make animal Y slightly better at doing X.
Enviroment similar to Colorado