Andor's Trail

I am wondering where i can get animal hairs, i remember seeing an npc who sells them, but i can not remember where

No NPC sells animal hairs, unless you sold them to him first.
You can get animal hair on some hairy animals. Go hunting to get some.

Spoiler : full list of enemies having a chance of dropping animal hairs

Yeah, i noticed that boars drop them

Do I need to keep all the things I have collected from my killings or can I sell them with impunity?

Thank you in advance.

It's your call. Some of them have uses, some will, some don't.
Before selling anything, always consider whether the money you get is worth risking to have to gain them back...

Thank you for the prompt response.