The Barnyard Animal of the Day is ...

... the emu. This is an emu:

Like all worthwhile creatures, emus were named after the sound they make. You'll know you're in the presence of an emu when you hear its majestic call, which goes a bit like this:

E-Moooooooooo!

(This knowledge proves to be especially useful in later verses of "Old Macdonald Had a Farm.")