Who is the most profitable for a small scale farm?

[Kessel23]

I am not really planning to get any Ostriches, Emu, or Rheas any time soon but I know I will eventually... Maybe in a few years. My mom always wanted Ostriches and she was thinking about getting some but I told her we do not have the room or knowledge to farm Ostriches, yet. We do have around 75 acres so I am sure we have enough room but we do not have any shelter or fencing up that we are not using for either chickens, rabbits, or dogs. Buuuuut I was kinda curious about these large birds and how profitable they are, if at all. So who is the most profitable, Ostriches, Emu, or Rheas? Also, how are they the most profitable, do you sell eggs, meat, or chicks? I was thinking, if I do ever get Ostriches, Emu, or Rheas I would probably get around 5-10, I am not sure if that could be profitable though, I would not want to spend money on 10 massive food guzzlers if I would lose money in the long run.