I still have some hair from my first pony from over 40 years ago. It is in a little tin and still looks the same as when it was new so don't worry too much so long as you keep it dry and out of the sun.
So sorry for your loss. I have most of My Sec A's tail (felt horrible taking it - but the whole thing was horrible.) and it has kept just fine the last few years. My understanding it that as hair is a dead structure anyway it keeps for decades without a problem. But you might want to ask the view of a taxidermist. I fully intend to get bits of hair woven into jewellery for my daughter & I - but I haven't yet found "the" piece for him. RIP - both your and mine.
Is it just the hair or the complete tail? If its just the hair it should be fine, I would wash it, make sure its dried completely, then perhaps mount it in a box frame to show it off, people have jewellery made out of hair so I cant see a problem with it perishing.. if its the complete tail I would contact a taxidermist .
Thanks for replies. It is just the hair, not the complete tail. I have also thought about the jewelry, but for now just want to keep it safe until I feel 'ready' to do something with it. Reassuring to know it can last 40 odd years, never would have thought that!
I've got a piece of horsehair that is about 10 years old and kept in a keepsake box and still looks and feels exactly the same. Definitely have a look at the horsehair jewellery when you're ready. Very sorry for you and hope the hair will bring you fond memories of many happy times together. *hug*