Why should I hatch Tallbird eggs?

Solution 1:

The only real advantage of the smallbird and smallish tallbird is that some mobs don't run away from them. Birds like crows, redbirds, etc. won't fly away from them, so the smallbird can be an easy source of feathers and morsels.

I guess you could also herd them into a pen, and have your own tallbird farm.

So, to answer your question: as near as I can tell, the value is fairly limited.

Solution 2:

I find that the newborn tallbird is actually quite useful, not to mention cute. (But that's my opinion) But the way the newborn is useful is that it's very good at hunting the crows and Redbirds, along with the turkeys. (I don't remember their exact name) I also like to chase away baby beefalo from their parents, and then set the baby tallbird on it, also hunting it myself. I don't know about the smallish tallbird, my baby tallbird died before it became a smallish tallbird. (Rest in spaghetti, never forgetti)

But my main point is that the baby tallbird isn't that useless. You get a great supply of food (morsels from birds or drumsticks from turkeys)and feathers, until it either dies or becomes a smallish tallbird.