I have over 50 graptors including heavily mutated ones…and using the tek bino it’s become clear it’s the highest unmutated stat that determines what type of feather the raptor will give.

One of my raptors has 52 in oxygen as it’s highest unmutated stats while it’s mutated melee comes to 71 where 51 is the original unmutated and it always still gives only oxygen feathers.

I also tried leveling the same graptors health to over 80 in total and it still gives only oxygen feathers.

Thus I can only conclude it’s those unmutated highest stat that determines the type of feather.

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.