Probably the same way every other egg hatches.
Emu eggs are incubated and hatched by the male emu. Also, the male may incubate the eggs of several females within the same nest. During the time he sits on the eggs, his metabolic rate slows, he does not eat or drink at all, and he stands just a couple of times each day to roll and turn the eggs. Average incubation of emu eggs takes around 8 weeks.