According to the rules (I found nothing about this in the errata):
A Horde may make ranged attacks equal to the first digit of its Magnitude.
For very small or very large hordes this would becomes weird. The first digit of 9 is 9, the first digit of 100 is one.
Funny if you ask me. It seems in a small horde the individuals becomes more motivated, in a large horde the hinder each other
.