I have had some experience with emus up close and personal. They are not usually aggressive (unlike cassowaries, who will quite literally kill you. As in dead), but they know they are bigger than you and will expect you to share your lunch.
Dude. No. Do not feed those emus without permission. They look like they're in a zoo or something. Enclosure = people put them there, plus they're emus. In Idaho. They did not walk there. Talk to the people who put them there before you go feeding their emus.
I will ask the owner if I can feed them. They are in a petting zoo area with goats so I figured I was allowed to at least pet them possibly on the head. I did feed the goats but I wonder if the emus will eat the goat food from my hand also.