||~11cm long excluding the hook, 3-4cm wide.
Peacock feathers are naturally a bit of a mixed bag, so there's always going to be some variation.
If you want big feathers, you have to use the ones from the very end of the tail, which are the oldest feathers so they have a lot of natural wear and tear, plus they drag on the ground when the peacock isn't displaying them so they end up looking dirty, faded, and tatty.
If you want nice-looking feathers, you have to use the ones near the base of the tail, but the younger feathers are always smaller in size, so you've got the trade-off between nice, crisp, smaller feathers and huge, tatty faded feathers.
These earrings generally use base feathers, so they are nicer-looking and smaller.
EVEN MORE IMPORTANT NOTE:
ABSOLUTELY NO ANIMALS WERE HARMED IN THE MAKING OF THESE EARRINGS!
I know a lot of people think you have to kill the peacock to get their feathers, but this is (thankfully) a myth. I am an animal rights activist and would never, ever sell a product that requires harming a living creature to make. Peacocks naturally shed their tail feathers at the end of the mating season, so there's absolutely no need to harm the peacock to get their feathers. You just follow 'em around and pick up the feathers when they fall out, which is... frequently. We had a couple of peacocks on our farm when I was growing up, and I swear there were feathers everywhere in mating season. We had so many that we ended up throwing them out by the handful just to get them off the lawn!