That's not a multiplication by 100, that's a bug. Not percents, but probably reproducing so much they hit a cap.
Well of course it's a bug. I'm just trying to analyze the behavior. If it's a cap, then it's a variable cap by site.
Other sites:
24: R<A2>niradipane, "Wiltskunks", forest retreat
Owner: The Bean of Immortals, elves
Parent Civ: The Most Mirth, elves
236 elves
11 toads
12 ravens
11 sparrows
100 horses
550 jaguars
14 green tree frogs
12 opossums
10 goblin outcasts
2 elf outcasts
7 human outcasts
25: Sothbodlapa, "Blockadefeed", hamlet
Owner: The Russet Coalition, humans
Parent Civ: The Confederacies of Holiness, humans
lord: Mim Distinctstable, human
67 humans
18 cats
600 horses
18 ducks
1 dwarf prisoner
3 human prisoners
1 elf prisoner
30: Kethilen, "Youthdays", hamlet
Owner: The Group of Scarring, humans
Parent Civ: The Empire of Tweeting, humans
lady: Osush Bridgebreaths, human
89 humans
7 turkeys
600 horses
8 ducks
9 pigs
You see? I might expect to see 6 horses in the hamlet of Youthdays, but there are 600. The number is
always a multiple of 100, and subjectively it's about 100x as high as one would expect based on other animals in the same site (except maybe in the elven forest retreat).
And check out the goblins:
26: Edzumzom, "Boredfiend", dark fortress
Owner: The Demon of Bodices, goblins
Parent Civ: The Laborious Monster, goblins
lady: Bosa Menacedtells, goblin
225 humans
20 elves
2 dwarves
9227 goblins
1 lizard fiend
4600 trolls
4600 ogres
4600 beak dogs
37 human prisoners
4 dwarf prisoners
8 elf prisoners
The trolls, ogres and beak dogs may also have "horse syndrome". 4600 of each is a suspiciously round number. Granted, there are a
lot of goblins in that dark fortress.