Andrew Barton's "The Paragaon of Animals" (short story, slavery)

Old idea, but readable.

Story summary.

A recently colonized-by-humans world of Esperanza, terraformed by mysterious Precursors millions of years ago & seeded with earth life (this part completely unnecessary to story!), now has huge bird-like local animals called "strewth" that humans have began using as draft animals on farms. Cassandra Warkworth runs a nursery to raise these animals for sale to formers. As she learns more about the animals, she'll begin having doubts as to weather they're animals & not low-tech sentients...

Fact sheet.

First published: Analog, March 2013.
Rating: B.