Pigs became pink sheep!!!

BUG:

What I expected to happen was...:
Gong into the wild and kill some pigs for food.

What actually happened was...:
I found that the pigs had all transformed into pink sheep (can' t naturally be found) and when I killed them it gave me pink wool.

Steps to Reproduce:
I think all the pigs transformed the moment I killed the first pig, but i' m not sure.