I don't like seeing the birds die, which is the reason I can't bring myself to use it and/or Bird Up!. However, I have a very good idea for both mods, which, I assume, can be easily made with XML. I'm just too much of a lazy ♥♥♥♥ to learn how to do it...

A rare joy building acquired via rewards or through exotics traders, which boosts mood in an AoE range around itself: Perched Bird! A ~1 metter long vertical perch with a bird on top. The bird's sprite can either change every now and then, as if the bird was moving, or remain stationary using the east sprite. The bird would produce its sounds as normal. It may also train Animals skill when colonists interact with it. This would allow me to have the cute birds in my game :^)

There's a goofy step further that can be taken: adding spoken SFX to the speech-able breeds, taken from youtube bird videos. "What you're doing? Gimme kiss! Peak-A-Boo". They can even swear, and the swears could even be tied to a personality given to them by 1-2-3 Personalities Animals module.

In any case, I just really really really really really want a ccockatoo/cockatiel on a perch. :D

Was the hornbill (or any of the birds, really) intended to be a pen animal?

Was intended as I used them for zoo-like aviaris. Would you prefer non pennable?

Well, yeah
I like to see the birds flying around the base, and them trapped inside fences doesn't really click.
Also, they can be trained to attack/rescue, but they can't do it from inside the fences.

Aaand if you want to build a zoo, you can always assign them to a specific area.