"Pet farm animal" seems a little ironic:
9 CFR 1.1 [Title 9 -- Animals and Animal Products; Chapter I -- Animal and Plant Health Inspection Service, Department of Agriculture], farm animal means “any domestic species of cattle, sheep, swine, goats, llamas, or horses, which are normally and have historically, been kept and raised on farms in the U.S., and used or intended for use as food or fiber, or for improving animal nutrition, breeding, management, or production efficiency, or for improving the quality of food or fiber. This term also includes animals such as rabbits, mink, and chinchilla, when they are used solely for purposes of meat or fur, and animals such as horses and llamas when used solely as work and pack animals.”
Now I would call my chickens pets but they provide me with fresh eggs. The ones not laying anymore are just freeloaders

I can tell you I've heard of many a parent that made the mistake of buying a "pet farm animal". Cute when small...but they get bigger.