Well, the person that has the oldest account is over 1600 days "old"
Howrse started in 2007
Riding level 2 requires you to be ten days old on howrse
3 years old.
They wander around Howrse giving players goodies. You can no longer get them though, they were from a old promo.
You can castrate any male on Howrse up till the age of 8 years old.
The old version is just that, old. You can't play on it anymore.
Those are for the old achievements.
30 or older
You have to have had an account on Howrse for at least 10 days in order to visit the safe haven.
There is no super fast way but you could enter giveaways or if one of your horses dies of old age then you get a pass
2 years 6 months
yes and if they are not looked after properely
it should be when they are 2 and a half years