The old question rears its head again: in MLP, you never know who is a sapient person and not an animal. Has Zecora been mean to a poor bird, or has she played a prank on Mr Wilson, the grumpy neighbour?
Yeah, I generally run in my headcanon that all ungulates "have to" be sapient, have a culture and language, be people, etc; other beings might very well be (like diamond dogs and those giant spiders in the comic).
I mean, it's like in bog standard fantasy universes you have standard mammalian humanoids - humans, orcs, elves, what have you - but you also have lizard-people and bug-people.
"It's these feathers here, you see, That I must use to brew a special re-ci-pie I'm sorry, for the feathers I took, Were said to be needed from my book. I didn't mean to cause you pain, Just don't force me to feel the same!"
Honestly, Ostriches and emu are mean sons of guns. I had a teacher who had a friend that ran an emu farm. Two drunks came by and started flashing their brights trying to spook the birds. Mission accomplished, on hopped the fence and kicked in their windshield.