Since most of the tips for this item is in the tame's main tips page, hidden around, I figured I'd put into here as well for those looking specifically for info about the feathers.

You can pluck 1 (one) from the bird every 2 IRL hours. There's about a 50/50 chance (from my personal experience) to get just a plain feather, or a stat-boosted feather. Stat boosted feathers, when given to a female tame you're about to mate, will give the baby a XX% chance to to inherit the higher ______ stat from its parents when added.

To get a specific stat, max all points into that stat ON THE BIRD. Want a better weight stat chance? Max the weight. Melee? Max it. Health? Max it - etc etc. Keep the birds well protected if you're not maxing health, they can be a bit squishy at the lower levels.

These also work on aquatic tame's, I read somewhere not long ago that they were bugged for aquatic but I've used them on my basilo and mega a few times without issue (since the last major Abb patch).

Also, to save yourself some trouble, the level of the bird DOES NOT effect the feather stat chances. I've tamed a level 25, 80 and 120, the lowbie offers me the same chance at a stat feather as the higher one has. If there is a difference in the percentage added on the feather, I have not noticed it between them - all of my stat feathers have been within 10% of each other from first time encountering the stat feather, to now when all 3 birds are max level.