Echoes of the Rising
This is copied from the “Mount” section
Using the Handle Animal skill you can retrain an animal while raising it (rearing an animal). You teach an animal specific skills or feats in place of those it instinctively receives. Each feat or skill increases the DC to rear an animal by 2. For instance, if you purchase an Owl Egg it would require 2 months to rear with a DC 16 handle animal check. If you wanted to retrain its skill point from Perception to Stealth it would be a DC of 18. If, in addition, you wanted to trade its Weapon Finesse feat for Skill Focus Stealth it would be another +2 DC, for a total of DC 20 to rear.
If an animal is already domesticated and fully grown, you may attempt the same – but the DC is double what it would be rearing the animal. It takes the same amount of time as would rearing an animal.