# A farmer went out to sow his seed

"A farmer went out to scatter some seed in a field" or "A farmer went out to scatter some seeds in a field"

# some fell

"some of the seed fell" or "some of the seeds fell"

# it was trampled underfoot

"people walked on it" or "people walked on them" 

# the birds of the sky devoured it

"the birds ate all of the seed" or "birds flew down and ate all of the seeds"