are those emus wild, or something you keep on the sanctuary?
I suppose they could be dangerous, if, for example you got between a mom and her chicks?
Our farm has both domestic livestock and incoming wildlife. We have 50ha of biodiverse nature reserve, adjoined by similar areas on the south and west boundaries. Wild emus and kangaroos live in these areas and come out onto pastures. They roam large tracts of bush and farmland by going through or over fences.
With emus, it is the male who raises the chicks. The Australian bush affords little nutrition compared to wildernesses on younger geology like you have in the States, and like in Europe. So our marsupial mammals typically run at around 2-3 degrees C lower core body temperature than most placental (non-Australian) mammals, to conserve energy. The koala sleeps a lot in the daytime and whenever not actually feeding.
So the female emu needs a big holiday after producing the eggs. She has to go off and look after herself and get the best nutrition she can to recuperate. The male, whose energy and resource expenditure in producing the fertile eggs was comparatively low, has the reserves to raise the chicks and therefore does it.
Male emus like looking after their young and have been known to try to steal other males's young when they can, to raise!
They do get very protective when they have young, but wouldn't ordinarily attack herbivores on pasture as they aren't a threat. Dogs, on the other hand, and overly nosy humans had better watch out! Riders are generally safe unless they dismount and so become recognisably human.