That depends on how you want to use it.
Fed, as the past tense of "to feed," can be used to show the act of eating, or the act of serving:
I fed the dog.
or
The vulture fed upon the carcass.
It is also a slang term for law enforcement agents from any federal law enforcement agency, in which case it would be used as a noun.
I am fed up with waiting for the phone to ring.
Example sentence - She fed the rabbits a carrot each day.
My inquietude was fed by the midterm i had later that day.
the horse was fed some hays.
He was force fed laxatives to purge his systems of fecal matter.
The man fed a bunch of pigeons in the park, during his lunch break.
The region contains most of the country's rain-fed argiculture.
Johnny didn't format his assignment correctly. Because of this, he was fed to the Mexicans.
To be fed
I was fed up with my wife's lazy behavior.She was fed up with my insistence she work all day.
Maize is an arable crop, that is fed to hogs, and human also eat it as 'corn on the cobb'.
Example sentence - The wolves pups looked well fed and cared for.