So I bought two eagle feathers off of marketplace for 100 each. I used one on one wolf, Ghostbur, and went to use the other one on my wolf, Newro, but the feathers gone. Has this happened to anybody else?

Unburied items can be stolen at night or by other packs. If you didn't get a stolen item alert then it was the former.

i used it literal moments after i bought it. the chances of it being stolen in a 30 second window is low.

Not sure if you can use a bald eagle feather on a wolf twice, but if you can, maybe you double clicked on accident and it used both feathers?

You cant. Its only used once.. so you couldn't have double clicked

You can actually apply 2 or more bald eagle feathers on a wolf, but only the first one will have effect, the others will just be wasted.

What if you didn't have enough mush or something?

i had over 1000 mush on me at the time of buying, and i only clicked once, im pretty sure ^^ but aye, i couldve clicked twice. that might be what happened here