Well, Greater Rhea family values anyway. Which are instructive. A fairly common sight on the Pantanal in Brazil:
The males courts and fertilizes a number of females, all of whom lay their eggs in his nest. And then leave. Probably to find another male. So the males care for the kids until they are grown. Males are simultaneously polygynous and females are serially polyandrous. In practice, this means that the females move around during breeding season, mating with a male and depositing their eggs with the male before leaving him and mating with another male. Males on the other hand are sedentary, attending the nests and taking care of incubation and the hatchlings all on their own.
The chicks stay pretty close to their (probable) dad.
The white blobs in back are termite mounds, making the Pantanal sometimes look like a thinly populated graveyard.
Greater Rhea adults have an average weight of 44–60 pounds and often measure 50 to 55 inches long from beak to tail; they usually stand about 4.9 feet tall to the top of the head. They are by far the largest bird by weight in the Western Hemisphere. They are also flightless. The males are generally bigger than the females. Large males can weigh up to 88 pounds, stand nearly 6.0 feet tall. A predator has to be very hungry to mess with a Rhea.
Nature is endlessly creative. There is no One Right Way, only the way that works in evolutionary terms.