in all fairness though they're very cute and there's nothing wrong with making the entire outside portion of your fortress a giant equine/goat/cat/bird sanctuary for your animal trainers to frolic in while you send miner after miner to their watery graves (after all three of the fortress' military squads were killed or maimed fighting two forgotten beasts that made their way out of the caverns into the hallway leading up to the fortress) in the cavern fifteen layers beneath all the unicorn vomit....we're rich in rope reed and barley
You have to neuter the entire lot except for like a male and a few females to keep for breeding or they'll overrun your base and take too much to feed. I'll sometimes drop pod animals at nearby bases to improve relations but most animals are pretty heavy and expensive to transport that way.