Game Mechanics: A large snake rattle doesn't seem to drop

[Veeshan]

Greetings.

I've tried to farm 'a rattlesnake', 'a large rattlesnake' and 'a kerra snake' which are supposed to drop 'a large snake rattle' used to craft research training runes and got no success after hours doing it in various places (Erud's crossing, North Ro, Commonlands).

I use to check vendors too and got no success.

Maybe I'm very unlucky but could you check if this item is in these creatures' loots table, please?

Thank you in advance.